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Username Post: building a 383, things to think about        (Topic#131229)
grumpyvette 
Senior Chevytalk Moderator -- Performance Subject Matter Expert --
Posts: 17142
grumpyvette
Age: 70
Loc: FLORIDA USA
Reg: 03-16-01
05-10-06 06:38 AM - Post#932305    

this is the type of challange/upgrade I work on for the guys all the time, AND IM CERTAINLY NOT SUGGESTING YOU CAN,T REACH YOUR GOAL,THRU OTHER ROUTES, BUT THAT APPROCHING THE PROBLEM LOGICALLY ITS FAIRLY EASY TO PLAN YOUR GOALS AND COURSE TO ACHEIVE THEM,
the first thing youll need to get strait in your mind is the realistic budget youll be willing to work with and that performance is basically the result of the power to weight ratio and HOW effectively you can get the power to the ground. keep in mind that for a street car your NOT building the engine for max peak power, your looking to build for the best average power/tq curve over the rpm range youll use most

AND THAT HAVING SLIGHTLY MORE HP THAN THE MINIMUM REQUIRED IS SMART, simply because you won,t always have the ideal tune or traction available,its silly to shoot for minimum levels yet its a waste of money to over build the engine, to levels youll seldom use or even want, as theres always compromizes in driveability

ok first Id point out that its silly to build anything smaller than a 383 displacement simply because youll make significantly greater total power from a larger engine than a smaller one,COSTS for a 383 are just not that much higher than a 350, and its TOTAL POWER not horsepower per cubic inch your interested in!

next,CORRECTLY MATCHING the cylinder heads, cam and compression ratio , to the rpm range where youll get the best results is where youll make most of your power potential.

think it thru before buying parts, and only sellect those components that match your goal,by far the most comon mistake is randomly sellecting mis-matched parts because you "GOT A DEAL"

ok lets look at your options, to keep costs reasonable we want to use what we can from your current engine but its insane to limit yourself to parts that restrict your potential power levels severly like the current heads,intake and rear gear ratio.



the formula for hp is (tq x rpm/5252=hp
example
450 ft lbs of torque at 3000rpm=257hp
450 ft lbs of torque at 6000rpm=514hp
because the torque is available at that higher RPM RATE and at the higher rpm useing gearing the rotational force the engine supplied can be applied faster or slower to the rear tires

here read these ALL CAREFULLY
http://www.69mustang.com/hp_torque.htm

http://www.ubermensch.org/Cars/Technical/hp-tq/

http://vette.ohioracing.com/hp.html

http://auto.howstuffworks.com/engine1.htm

http://auto.howstuffworks.com/horsepower.htm

http://auto.howstuffworks.com/question622.htm
where most guys go wrong is in not correctly matching the cars stall speed and gearing to the cars tq curve, if you mod the engine for increased high rpm performance but fail to also match the stall speed and gearing to that higher rpm tq curve much of the potential improvement is wasted.


calculate, your minimum hp levels needed

http://www.runeb.org/www_docs/Jexoticasite/frames/horsepowercalc.htm

http://www.stealth316.com/2-calc-hp-et-mph.htm

http://www.gordon-glasgow.org/hpcalc.html


a few calculations will quickly point out that your realy looking to have between 350-400 rear wheel hp, that basically translates into an engine making about 18% higher power at the flywheel, so lets assume or goal is a 420-450 hp engine, now your basic 383 will be correctly designed and matched to a rear gear ratio in the 3.73-4.11 rear gear so youll maximize the area in the torque curve that can give the best results, the 2500-6000rpm band. so thats where we NEED TOO concentrate our efforts. this should point out the stall speed of about 2500-2800rpm is ideal in this application to match your needs


look at this chart, it shows the ideal durration for best results at differant rpm bands, well want the MINIMUM DURRATION that will supply our needs thats going to be in the 220-230 range for street use,while the 230-235 range would be about ideal for power.
we quickly find that durration will match to a 10:1-10.5:1 cpr if we want to use pump gas.

ok,now the CYLINDER HEADS and intake NEED to supply that RPM RANGE and DISPLACEMENT, youll want a set of heads that flow about 230cfm AT .500 lift at the least,to easily match that requirement.

currently this is a good choice in performance per dollar in heads

heads

http://www.jegs.com/webapp/wcs/stores/se...7&langId=-1

cam

(READ THIS)
http://www.idavette.net/hib/camcon.htm


(minimum cost flat tappet hydrolic)
http://www.crower.com/misc/cam_spec/cam_finder.php?part_num=00231&x=35&y=13

http://www.cranecams.com/?show=browsePar...rtType=camshaft

upgraded ROLLER CAM
(what IM useing in my similar engine)

http://www.cranecams.com/?show=browsePar...lvl=2&prt=5

(what ID use if I was to build it again)

http://www.crower.com/misc/cam_spec/cam_finder.php?part_num=00471&x=20&y=9


stroker kits

http://www.speedomotive.com/383%20Mighty%20Mouse.htm


http://www.naparts.com/ProductModelDetail.cfm?ProductModelId=1674
http://www.speedomotive.com/383Forged.htm

oil pan
http://www.midwestmotorsportsinc.com/order_part.php?item=CP100LT&line=MWM

to answer some questions

WHATS REQUIRED?

installing a longer 3.75 stroke crank assembly
Ive built dozens of 383 and 396 sbc engines and the clearancing can be done BY YOUR OWN HANDS with a standard HAND HELD drill and a few CARBIDE BURRS OR GRIND STONES in that drill in well under two hours if you take your time and total expence even if you need to buy that drill and burrs will be well under $50 total
http://www.click-onsource.com/Merchant2/merchant.mvc?Screen=CTGY&Category_Code=O VAL_1-4_Shank

buy a 1/2" burr and a cheap drill

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=20776&it em=4358782476&rd=1

place you old bearings in the block an place the crank in those bearings after coating them with axle grease
slowly rotate the crank and grind a minimum of .060 clearance anywhere the counter weights might touch the block and try NOT to grind more than about .070 any place it touches the block (use a JUMBO size paper clip as a gauge if you don,t have feeler gauges)
next assemble two connecting rods and pistons, one connecting rod and piston for the left one connecting rod and piston for the right, use old bearings coated with axle grease and no rings on the pistons, assemble them to the crank and grind anyplace the rods touch the block, grind minimum of .060 clearance and try NOT to grind more than about .070 any place the rods touche the block (use a LARGE size paper clip as a gauge if you don,t have feeler gauges)move them to the next journal and repeat untill all 4 journals and 8 connecting rods clear. now assemble all eight rods and pistons without rings and install them in thier correct locations and recheck everthing carefully.
next intall the cam and index it correctly with the timeing chain/gears, rotate the engine slowly and look for clearance issues, between the cam and rods/rod bolts ,youll need to use a small base cam if there are major clearance issues but in most cases if your cams lift and duration is under about 230 at .05 and .500 lift there should be minor if any clearance issues, usually the outside edge of a rod bolt head is the only area needing a touch up.

once everything clears, wash all the parts VERY CAREFULLY ,TWICE and re-oil then send out to be ballanced now you might ask why do that! well, first youll know its done correctly, and that a correctly built 383 will have a very significant hp and torque advantage over any similar 327 or 350

how much power I'll get.

that of couse depends on the combo, cpr, cam,ETC. but you can assume about a 40hp/40 ft lbs increase over a similarly built 350
http://www.cranecams.com/?show=browsePar...lvl=2&prt=5

heres the SMALL BASE CAM I USE IN MY 383
NOTICE it has a .900 base circle



http://www.newcovenant.com/speedcrafter/tech/camshaft/1.htm

"The camshaft is a straight metal shaft with bumps on it. The bumps are called lobes. The gray area in the picture is the shaft's "base circle." The blue area in the picture is the lobe. The area of the base circle opposite the lobe is the "heel." The tip of the lobe is called the "nose" or "toe." (Get it? Heel? Toe?) As the camshaft rotates, the engine's valve lifters (called "followers" in overhead cam engines) ride on the surface of the base circle and the lobes. When a lobe passes under the lifter, the lifter is pushed up. The lifter is connected to the top of a valve by various means (depending on the engine), and pushes the valve open.
Between the edges of the lobe and the heel are areas called "Clearance Ramps." These are places that are higher than the base circle, but only slightly. When the lifter is on the clearance ramps, it moves very slowly. The valve is not open enough to pass any significant amount of air or exhaust, but it is open. The clearance ramps are there to reduce forces on the valve train that could tear it apart or allow the valve to slam against its seat in the cylinder head.
The distance between the base circle and end of the toe is the lift. More specifically, as you will see later, it is called the "lift at camshaft."

most cams have a base circle closer to a diameter between 1.1" and 1.2"

ID STRONGLY suggest getting a CRANE CAM thier QUALITY seems to be far better than some others I could name


a small base circle gives more clearance because your cam lobe lift is the differance between the base circle and the lobe nose, lets assume a .500 lift on a chevy sb
they normally use a 1.5 ratio rocker so the cam lobe needs to be .3334 tall , so with a standard base circle the lobe nose swings in a circle thats about 1.766 in dia.
(
a small base circle cam like my crane with its .900 dia. with the same lobe would only spin in a circle thats about 1.568 in dia. giving about 0.100 inches MORE CLEARANCE TO THE POTENTIAL ROD/CAM CONTACT AREA

Detonation vs power

some of the major factors in your engines potential power, is the volumetric efficiency (how efficiently you fill and empty the cylinders) and the octane of the fuel used, compression ratio and detonation limits,
With detonation, prevention the main factors are
Ignition timing
Quench
FUEL OCTANE
DCR
and cylinder heat level
you’ll be fairly safe if you stay under
8.5:1 dcr at 170f degrees
8.25 dcr at 180f degrees
7.8:1 dcr at 210f degrees
and keep the quench in the .036-.043 range
heres some differant calculators
http://www.kb-silvolite.com/calc.php?action=comp2
http://www.wallaceracing.com/dynamic-cr.php
http://www.smokemup.com/auto_math/compression_ratio.php
http://not2fast.wryday.com/turbo/compression/cranking_pressure.shtml
average the results

the numbers are for 92 octane premium gas run at a 14.7:1 a/f ratio

BTW heres a VERY SIMILAR GRAPH



richen up the mix to 12.5:1 for max power/tq vs low emmissions and you can cheat slightly as the cylinder temps go down slightly.
keep in mind ALUMINUM absorbs and allows the transfer of heat to the coolant at a much faster rate, so your less likely to have cylinder temps raise into the detonation range as quickly.
and it should be obvious that your igntion curve and spark strength will also effect results, personally Ive found the BETTER MSD multi strike ignitions keep the cylinders cleaner and less likely to detonate

btw, reading material

http://www.kennedysdynotune.com/Dynamic%20Compression%20Tech.htm

http://www.misterfixit.com/deton.htm

http://www.federal-mogul.com/cda/content/front/0,2194,2442_7359_7525,00.html

http://www.diabolicalperformance.com/hotrodoctane.html

http://www.sdsefi.com/meltdown.htm

http://www.procharger.com/intercooled.shtml

http://www.kb-silvolite.com/article.php?action=read&A_id=36

http://www.chevyhiperformance.com/techarticles/94138/

http://racingarticles.com/article_racing-10.html

http://www.popularhotrodding.com/tech/0311em_power_squeeze/index.html



 




ChevyNova79 
Senior Member
Posts: 264
ChevyNova79
Loc: Chicago Suburb
Reg: 10-09-03
Re: building a 383, things to think about
05-10-06 07:57 AM - Post#932306    
    In response to grumpyvette

Great post grumpy. I haven't finished reading it yet, but I had one question. Is there anyway to get the camshaft selection chart bigger? Its too small to read everything on it, unless there was a link to it I missed.

But so far I really appreciate the post, since I'm thinking of putting in the money for a 383.

79 Nova http://www.cardomain.com/memberpage/532696


 
doc1 
Senior Member
Posts: 457

Reg: 06-23-03
Re: building a 383, things to think about
05-10-06 07:58 AM - Post#932307    
    In response to grumpyvette

Grumpy.
You have taken a lot of time, and written a comprehensive tutorial. I did about the same thing with mine, except, the person who built my engine had a jig to grind the contact points on the block. I went with a real mild cam and I have never looked back.
In my opinion, you wrote a real comprehensive, makes sense article. Good job.
I really like my engine. The 383/350 is a good runner.

In the beginning was the Floyd, the Floyd was with him, and he was with the Floyd. Syd Barret left right after the happening.
Big blocks rule!


 
MikeB 
Ultra Senior Member
Posts: 10058
MikeB
Loc: Plano, TX
Reg: 08-28-03
Re: building a 383, things to think about
05-10-06 03:48 PM - Post#932308    
    In response to grumpyvette

Damn, just when I thought I wanted a 327!

What compression ratio/solid cam/heads would you recommend for a street-only 383 with wide ratio Muncie, 3.42 axle, and 26" tires? I'm guessing 9.5:1, 215-220 intake duration, and 180cc heads.


1982 C10 SWB pickup: Unmolested base truck, original paint. Originally had 250 six and 3-on-the-tree
Now has 355 with Vortec heads, RamJet roller cam, LS6 beehive springs, TH350
Retired, but working part-time on 50s-70s cars & trucks.


 
305Chevy 
Member
Posts: 76

Loc: Lincoln, Nebraska
Reg: 08-02-04
Re: building a 383, things to think about
05-10-06 07:28 PM - Post#932309    
    In response to grumpyvette

All I can say is wow. Grumpy, you give enormous amounts of advice and instruction. I was debating between a 350 or a 383 build; I now know what I'll do. Thanks.

'84 Caprice: 600cfm Eddy, RPM intake, ported 416 heads, rear frame brace, 9C1 police swaybars, Monroe Sensa-tracs


 
CNC BLOCKS N/E 
Senior Member
Posts: 974
CNC BLOCKS N/E
Loc: NORTH EAST
Reg: 12-12-03
Re: building a 383, things to think about
05-11-06 02:46 AM - Post#932310    
    In response to 305Chevy

Quote:

All I can say is wow. Grumpy, you give enormous amounts of advice and instruction. I was debating between a 350 or a 383 build; I now know what I'll do. Thanks.




Do you know of a guy Mark Burch who builds sprint car engines as we machine some blocks for those guys as there cars seem to run good where ever they run.



 
salazar44 
Senior Member
Posts: 835
salazar44
Loc: los angeles, ca
Reg: 04-18-05
Re: building a 383, things to think about
05-11-06 06:06 AM - Post#932311    
    In response to CNC BLOCKS N/E

Did somebody say sticky!!!!!!!!!!!!!!!!!!!!!

VIC One Repair Leads to Another! My 65 Chevy C-10 Blog


 
305Chevy 
Member
Posts: 76

Loc: Lincoln, Nebraska
Reg: 08-02-04
Re: building a 383, things to think about
05-14-06 07:45 PM - Post#932312    
    In response to CNC BLOCKS N/E

Quote:

Quote:

All I can say is wow. Grumpy, you give enormous amounts of advice and instruction. I was debating between a 350 or a 383 build; I now know what I'll do. Thanks.




Do you know of a guy Mark Burch who builds sprint car engines as we machine some blocks for those guys as there cars seem to run good where ever they run.




No, I can't say that I do. I'm just a 19 year old kid who lurks around here trying to learn as much as I can.

'84 Caprice: 600cfm Eddy, RPM intake, ported 416 heads, rear frame brace, 9C1 police swaybars, Monroe Sensa-tracs


 
grumpyvette 
Senior Chevytalk Moderator -- Performance Subject Matter Expert --
Posts: 17142
grumpyvette
Age: 70
Loc: FLORIDA USA
Reg: 03-16-01
Re: building a 383, things to think about
05-16-06 09:05 AM - Post#932313    
    In response to 305Chevy

this may help also

http://www.bracketmasters.com/small_block_stroker_383_cu.htm

http://www.prewittracing.com/newpage2.htm



need a few pictures?
this may help
the comon areas are the area near the block oil pan rail where the rod bolts touch
and the lower inner cylinder walls and where the cam lobes touch the rod bolts upper shoulder on some types of rods, now you can,t grind on the cam, but you can grind the edge of the rod bolt and you can use a small base circle cam to give greater clearances







http://www.karl-ellwein.org/2005engineprojects/388project.htm






"What do you think about hard blocking the bottom inch of the block?"

hard block porded in the cylinder base area up to the level of the bottom of the freeze plugs has little effect on the cooling and adds significantly to cylinder strength on thin bore walls, so yeah! any time you exceed about a ..040 overbore its a good idea. as it significantly strengthens the blocks walls

GOOD
http://store.summitracing.com/default.as...p;x=19&y=11

MUCH BETTER, because it gets into the fine cracks and pores in the cast block surface, as its a liquid epoxy and holds far better than the basically structural concrete that moroso sells

http://www.matweb.com/search/SpecificMaterialText.asp?bassnum=PDEVCON05

IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!


 
grumpyvette 
Senior Chevytalk Moderator -- Performance Subject Matter Expert --
Posts: 17142
grumpyvette
Age: 70
Loc: FLORIDA USA
Reg: 03-16-01
Re: building a 383, things to think about
05-18-06 03:22 AM - Post#932314    
    In response to 305Chevy

QUENCH??
http://www.100megsfree4.com/dictionary/car-dicq.htm

quench area:
A zone in the combustion chamber where the piston at top dead center is very close to the cylinder head. Because the piston and cylinder head is cooler than the unburned part of the fuel-air mixture (i.e., end gas), they pull the heat from the end gas. Because the end gas is now cooler, detonation is quenched or reduced. However, the process does form unburned hydrocarbons.

SQUISH
An area in the combustion chamber of some engines where the piston squishes or squeezes part of the fuel-air mixture at the end of the compression stroke. As the piston approaches top dead center, the mixture is pushed out of the squish area and this promotes turbulence, further mixing of the fuel-air mixture and more efficient combustion

run less than about .035 thousands and at high rpm levels the pistons might hit the cylinder heads, run more than about .044 thousands the QUENCH effect of forceing the fuel air mix to the center of the cylinder from the cylinders edge area looses both speed and effectiveness, remember the quench area must be so tight that virtually all the fuel/air mix is forced (squished) into the center area and none is allowed to burn untill its squirted into the burn area increaseing turbulance and burn efficiency
in theory the much better quench, combined with the shorter more compact area the flame front needs to cover and the far higher turbulance combine to allow more of the pressure to build AFTER the crank passes TDC on the end of compression and begining of the power stroke

its mostly an advantage in that you get a more even and FASTER burn in the cylinder and less chance of detonation, simply because both the lower time and faster pressure curves favor the ignition flame front vs detonation
look, it takes approximately 40 thousands of a second for the flame from the ignition to cross a 4.25" bore,at low rpms and still takes about 15 milliseconds at high RPM due to the much faster movement of the compressed fuel air mix in the cylinders, lets look at what that means
if the chevy plug is located 4/5ths of the way to one side thats a time of about 32 thousands for the pressure to build as the flame travels 3.4" in the chevy but in a compact combustion chamber it could only take the cylinder flame front less than 10-20 thousands of a second to travel acrossed the combustion chamber for a complete burn at low rpms, this of course speeds up as the swirl and turbulance increase with increased engine RPMs but the ratios stay similar. this results in more useable energy WORKING on the piston AFTER IT PASSES TOP DEAD CENTER ON THE POWER STROKE. BUT MODERN WEDGE combustion chambers use increased QUENCH to speed the flame front and lower the burn time combined with a smaller combustion chambers.
the differance may be easier to grasp if you think of the quench area as a significant part of the total combustion chamber voluum,thats forcing its potential fuel/air mix into the central combustion chamber as a jet of highly compressed F/A mix, like the differance between lighting a cup of gasoline by simply placing it next to a camp fire vs throwing it violently into a camp fire

look at this chart
http://www.iskycams.com/ART/techinfo/ncrank1.pdf

keep in mind that the cylinder pressure starts, builds to a peak and drops off all before the piston moves more than about 1/2 inch away from TDC and that if your wasteing 10-20 degrees of rotation compressing the burning mix in a slow to ignite combustion chamber your wasteing engine power
http://chevyhiperformance.com/techarticles/94138/

http://naca.larc.nasa.gov/reports/1939/naca-tm-914/

http://www.me.gatech.edu/energy/ICEngines/8_CylinderCombustionProcesses.pdf


http://www.nedians.8m.com/Comp_IC.html

http://mb-soft.com/public2/engine.html


[

LOOK CLOSELY AT THESE PICTURES

you only have QUENCH if theres a flat area on the piston that mates to a matching flat area on the combustion chamber roof, on these pistons dual quench areas throw the compressed fuel/air mix to the center from the twin quench areas
notice, if used with this head, that only one side would have a fairly large and EFFECTIVE QUENCH area ,(the side away from the spark plug)



things to read
http://chevyhiperformance.com/techarticles/94138/

http://www.theoldone.com/archive/quench-area.htm



http://racehelp.com/article_racing-10.html



http://members.uia.net/pkelley2/DynamicCR.html



 
patman 
Member
Posts: 106
patman
Loc: Lakes Region, NH
Reg: 03-25-03
Re: building a 383, things to think about
05-18-06 02:16 PM - Post#932315    
    In response to grumpyvette

Grumpy...I'm honored you used my pictures! (last 3 of the rod clearance pictures are from my 406 build) Still workin' on putting it together...

http://www.bracketracer.com/engine/engine.htm

Pat



 
grumpyvette 
Senior Chevytalk Moderator -- Performance Subject Matter Expert --
Posts: 17142
grumpyvette
Age: 70
Loc: FLORIDA USA
Reg: 03-16-01
Re: building a 383, things to think about
05-18-06 03:45 PM - Post#932316    
    In response to patman

thanks for making them available patman
!
MY skills at posting CLEAR PICTURES Ive taken leave alot to be desired at times

IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!


 
partsdan 
Member
Posts: 1

Reg: 07-18-06
Re: building a 383, things to think about
07-18-06 03:51 PM - Post#932317    
    In response to grumpyvette

nice post as always grumpy.hope your doing good, im at a new dealership, ive got #'s if you want em. havent been here in a month of sundays. good to be back and i hope your doing good.



 
Thadd 
DECEASED Member
Posts: 11178
Thadd
Age: 78
Loc: Rolling Hills, Ca,
Reg: 12-30-01
Re: building a 383, things to think about
07-19-06 11:40 AM - Post#932318    
    In response to partsdan

Another thing is to bolt the pan on and check clearances again. Somehow, during the building of one of my 383's, the original Corvette pan that I had clearanced got swapped for one that went on a customers car. When I installed the pan, the engine went right into the car. When it was fired, it had a very obvious knock. Pulling a 383 out of an S-10 is a pain, but it had to be done.
One rod bolt was hitting the pan rail just above the oil filter. One whack with a hammer fixed it. I know to measure twice whack once, but in this case I got in a hurry and didn't do the final checks as I should have and it cost me....

Proud member of the BABY BLUE T-SHIRT BROTHERHOOD


 
grumpyvette 
Senior Chevytalk Moderator -- Performance Subject Matter Expert --
Posts: 17142
grumpyvette
Age: 70
Loc: FLORIDA USA
Reg: 03-16-01
Re: building a 383, things to think about
07-24-06 02:21 AM - Post#932319    
    In response to Thadd

heres a few things that should always be checked on an engine build

heads
are the pushrods perfectly strait?
do the pushrods flow oil?
rocker studs/guides torqued correctly?
do the head bolts have washers under the bolt heads? are they the correct length for the cylinder heads in use?
have the heads been pocket ported?
combustion chambers unshrouded?
intake ports gasket matched"
are the valve guides cut to the correct length?
are the heads pocket ported?
is the retainer to valve guide clearance correct?
are the valve guide oil seals installed?
is there valve spring seats installed?
inner damper springs installed?
spring bind height checked? (to exceed max valve lift by .050 min.)
oil return holes cleaned of casting flash?
were steam holes in heads necessary?
were the spark plug threads of a installed spark plug extending into the combustion chamber?
rocker slot to rocker stud clearances ?
retainer to valve guide clearances?
spring bind height checked for the correct spring pressure?
valve lash/preload ?
are the valve springs the correct tension,height?dia.
keeper the correct angle? style? size?
valve seats the correct angles?
valves back cut?
valves the correct length, stemsthe correct diam.
strait?
rockers the correct ratio?
were the valve to valve guide clearances checked?
were the heads milled?
did the head gasket overlap the bore?
what are your valve train clearances?
is the rocker arm geometry correct!
chambers CC,ed
port work..(some steps optional)

(1) open throat to 85%-90% of valve size
(2)cut a 4 angle seat with 45 degree angle .065-.075 wide where the valve seats and about .100 at 60 degrees below and a .030 wide 30 degree cut above and a 20 degree cut above that rolled and blended into the combustion chamber
(3)blend the spark plug boss slightly and lay back the combustion chamber walls near the valves
(4)narrow but dont shorten the valve guide
(5) open and straiten and blend the upper two port corner edges along the port roof
(6) gasket match to/with intake and raise the port roof slightly
(7) back cut valves at 30 degrees
(8) polish valve face and round outer edges slightly
(9)polish combustion chamber surface and blend edges slightly
(10) remove and smooth away all casting flash , keep the floor of the port slightly rough but the roof and walls smoothed but not polished.
(11) use a head gasket to see the max you can open the combustion chamber walls
(12) blend but don,t grind away the short side radias


block
is the oil pump pick-up mounted 3/8"-1/2" from the oil pan floor/
is the windage screen mounted about 1/8" from the rotateing assembly/
is the pick-up brazed to the pump body?
has the oil pump relief piston in the oil pump been checked for free ,easy movement? clearance? spring tension?
is the oil pump pick-up tube inserted too far into the oil pump body,(binding the gears)
has the block been clearanced for the rotating assembly?
has the block been aline honed?
is the crank strait?
are the damper install keyway and threads ok?
counter weights clearanced?
MAGNAFLUXED?
OIL PASSAGES CLEANED?
GALLERY PLUGS INSTALLED CORRECTLY?
has the cam to rod bolt clearance been checked?
piston to valve clearances checked?
piston to bore clearances?
TRUST BEARING CLEARANCE?
what were the piston ring to slot clearances?
RING GAPS?
were the rings all checked individually for end gap in the cylinders they were used/installed in?
were the rings checked to make sure the correct side faced up, and the correct ring was in each groove?
what were the back clearance on the rings?
were the oil ring expanders carefully fitted for correct drag?
were the oil ring scraper ring rails checked for end gap?
total cam lift and remaining clearanceS?
WAS THE CAM DEGREED IN?
main bearing clearances?
what is the main bearing run-out clearance
piston to head clearance? (QUENCH?)
head gasket to coolent holes checked?
magnets installed?
rod bolt to block clearances?
what tq reading is necessay to spin the crank with no rods attached?
are the rod bolts and main caps torqued correctly? (rod bolts checked with a bolt stretch gauge?)
did you check the block for a strait main cap alignment?
what size journals and what were the bearings edge to filet clearance??
are the journals checked for finish and run-out/tapper?
did you use moly lube to assemble?
correct bearing crush?
did you pre-lube before start-up?
did the distributor gear fit the cam gear precisely?
was the distributor oil flow mod done?
was the correct style distributor gear used?
did you check the piston to piston pin bores for fit and clearance?
did the piston pins to snap ring clearance seem overly tight?
if they are pressed pins were they correctly matched and checked for free movement in the pistons?
was the engine ballanced?
cam button installed?, and lock plate installed?
were the rods resized? checked for parrallel bores/were the rods strait?
piston valve clearance notchs correctly located on the pistons? edges smoothed?
were the rods checked for length?
is there a few thousands clearance on the oil pump drive shaft AFTER the distributors bolted down?
did you install a steel collar on the oil pump drive shaft?
was the rod to piston pin side clearance checked? (at 4 places seperated bye 90 degree spots)
does the oil pump drive shaft mid section clear the block with the pump installed?
whats the starter to flywheel gear clearance?
is the pilot bearing to trans imput shaft clearance ok?
is the front motor mount bolt to fuel pump pushrod clearance ok? did the fuel pump pushrod move easily/
are you possitive the pistons were installed with the correct valve relief in the correct location?(eiieeiie) were the pistons installed with the correct side facing forward/
what torque values were used on all fasteners/ were they the correct length and type bolts?
were the bores honed with a torque plate in place?
was the cylinder finish correct for the type rings used?
was the oil pump itself checked for free spin and clearance AFTER THE PICK-UP WAS INSTALLED?
was the cam drive checked for free rotation and drag/
were the oil passage plugs drilled for extra oil flow?
were the lifter bores checked?
cam to timing cover clearance?
cam journal to cam bearing clearances?
was the cam journal run-out checked?
was the cam degreed in or just lined up useing factiory index marks?
has the rod and windage screen to oilpan clearnce been checked?
does the dipstick & tube clear the windage screen?
was the cam lobes/LSA/LIFT CHECKED?
is the deck square/level?
whats the cross hatch hone angle?
what grit hone was used? is it correct for the rings used?
are all the threads clean/clear?
brass freeze plugs installed?
block painted?
a few things to check

are the connecting rods installed with the beveled edge facing out on each pair with the bearing installed with the bevel facing out on both the lower and upper rod bearings also?

are you using beveled bearing shells that match the cranks throw bevels?

what are the bearing clearances? (are they the same checking at 90.120.160 degrees from the first measurement?}

what are the connecting rod side clearances?

is the crank strait? has it been turned undersize? if so...on ALL the rods? on ALL the mains? or on ALL the BEARINGS JOURNALS OR ONLY SOME?

whats the TRUST BEARING CLEARANCE?

is the piston side clearance correct?

are the pistons installed in the correct cylinders? (intake and exhaust notches correctly located to match the cylinder head)

are you POSSITIVE each main cap is in the correct location and FACING THE CORRECT DIRRECTION?

did you use MOLY assembly lube?

did you check EACH INDIVIDUAL RING ON EACH PISTON for ring gap clearance,AND that the rings fit the piston ring slots correctly? are any rings installed in the wrong ring slots (2nd ring in top slot ETC,)or upside down

do the rings have back clearance?

were the cylinders CORRECTLY HONED?

is the cam drive binding?

does the crank contact the windage screen?
does the dipstick tube or dip stick touch the crank at any point?

is the oil pump /cam gear binding?

did you check that the oil pump mounting bolt does NOT contact the back surface of the rear main BEARING under the main cap?

is the block warped, checked carefully?,was it line honed?


are the piston pins centered? do the pistons rotate thru an arc with little resistance?

are there any lock pins, spirolocs, tru-arcs contacting the cylinder walls?

are you sure the bearing shells are installed correctly and the locating tabs are in the correct slots?
are they the correct bearings for the application? or did you just assume the part guy knew what he was doing?
did you MEASURE or GUESS, did you at least use Plastigauge and a torqure wrench?


did you check EACH AND EVERY journal for tapper and roundness

did you get the rotateing assembly ballanced???


____________________________________

retired engineer,engine builder, racer

IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!


 
coolvelle 
Senior Member
Posts: 54
coolvelle
Loc: Colorado
Reg: 09-08-06
Re: building a 383, things to think about
09-08-06 06:34 PM - Post#932320    
    In response to grumpyvette

This is an awesome post. Thanks!!

1972 chevelle 383 stroker/ 425hp, holley750 4150, Th350 3000 stall 3:90 gears MSD all the way! Living a childhood dream! http://www.picturetrail.com/uid6740038


 
grumpyvette 
Senior Chevytalk Moderator -- Performance Subject Matter Expert --
Posts: 17142
grumpyvette
Age: 70
Loc: FLORIDA USA
Reg: 03-16-01
Re: building a 383, things to think about
10-15-06 04:44 AM - Post#932321    
    In response to coolvelle

http://www.ryanscarpage.50megs.com/combos2.html

look thru this, the one factor that should become clear is that DISPLACEMEN, GOOD HEADS,COMPRESSION, and a decent MATCHED CAM will have a HUGE effect on your results, failure to use a decent set of heads will severly limit your power potential, figure on spending a minimum of 1/3 of the total budget on the heads and cam alone....and be aware you must match the rear gear and stall to the cylinder heads port size and the cams power band

IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!


 
livebeatdad 
Member
Posts: 2
livebeatdad
Loc: New Mexico, USA
Reg: 10-18-06
Re: building a 383, things to think about
10-18-06 05:26 PM - Post#932322    
    In response to grumpyvette

I am a wet behind the ears newbie and thank you in advance for your patience. I am wanting to built a 383 Stroker and this will be my 1st engine build (father, son, son, son project). I have a 72 Suburban, stock 350 motor/trans., 3.73 gears, quadrajet carb, 2.5 inch headers, 6 inches of lift and 35 inch tires.I was wondering if you might have any advice in regards to bang vs. buck. I found this kit:



Fully prepared block, magged, powerhoned, brass freeze plugs, cam bearings, pistons, reconditioned crank & rods, MI 77 bearings, moly rings, performance cam and lifters, FelPro gaskets, high volume oil pump, double roller chain, all parts balanced.
CHEVY CAST PISTONS FORGED
383 4 Bolt $1100.00 $1200.00

larryskit

Please forgive my lack of experience but I was hoping that you all might be able to recommend heads, intake and a carb for the finished product. We often tow and offroad as much as we can. Thanks again.

Any fool can make a baby, but it takes a man to raise a child!


 
kevindtimm 
Frequent Contributor
Posts: 1945
kevindtimm
Loc: Cedar Park, TX
Reg: 11-09-04
Re: building a 383, things to think about
10-19-06 04:37 AM - Post#932323    
    In response to livebeatdad

I'm no expert, but (IIRC) 2.5" headers would be huge (and mostly for high revs). Typical grunt headers would be of the 1 5/8" variety instead. Measure your tubes (at the head) that will give you a true reading (don't measure at the collecter).

2008 Equinox LS - My only Chevy right now


 
grumpyvette 
Senior Chevytalk Moderator -- Performance Subject Matter Expert --
Posts: 17142
grumpyvette
Age: 70
Loc: FLORIDA USA
Reg: 03-16-01
Re: building a 383, things to think about
10-19-06 07:07 AM - Post#932324    
    In response to livebeatdad

the kit you sellected looks like a reasonable choice for your application

Id suggest this cam, intake and heads keeping in mind that the build is designed for low rpm towing (TORQUE) as the prime design feature and LOW PRICE as a significant factor in parts sellected

http://www.cranecams.com/index.php?show=...lvl=2&prt=5

these heads (youll need two)

http://www.jegs.com/webapp/wcs/stores/se...ategoryId=19715

Action +Plus Intake Manifold>
1955-86 262-400ci w/Vortec (L31) heads
4150 Carb Flange
Idle-5500 RPM Range

925-8121

Designed to use stock GM intake gasket p/n 809-89017465
No EGR provisions
Permanent Mold Casting
Action +Plus Intake Manifold>
1955-86 262-400ci w/Vortec (L31) heads
4150 Carb Flange
Idle-5500 RPM Range

http://www.jegs.com/webapp/wcs/stores/se...ategoryId=15917


tPerformer Series Carb
600 cfm
Electric Choke
50-State Legal for All Pre-1980 GM V8's
Maximum Fuel Economy Calibrated

350-1400

http://www.jegs.com/webapp/wcs/stores/se...ategoryId=12625



 
63ss409 
Member
Posts: 20

Reg: 02-13-03
Re: building a 383, things to think about
11-24-06 01:23 PM - Post#932325    
    In response to grumpyvette

Grumpy,
Need some advice on a 383 for my '87 Vette. Its a daily driver, auto xsmn, 3.07 rear. I was considering a Scat cast 3.75 "internal balance" crank (has larger counterweights but has to use 6" rods), Scat stroker rods (6"), and a ZZ4 cam that a friend gave me from his crate engine. I have a set of alum. 58cc 113 heads that will be mildly ported, an accel intake manifold, LPE large tube runners, and a mildly ported plenum. I will have the block decked for better quench, but I am undecided on pistons and need to choose these first. I was looking at Wiseco forged dished ones, but they are a bit expensive. Can I go with a good set of cast ones to save a little cash? What are the pro's and con's of each? (forged vs cast). This car will never see the track or rpm beyond 5500.



 
1FATGMC 
Senior Member
Posts: 336
1FATGMC
Loc: Southeast Utah
Reg: 04-29-04
Re: building a 383, things to think about
11-24-06 02:33 PM - Post#932326    
    In response to 63ss409

Quote:

Grumpy,
Need some advice on a 383 for my '87 Vette. Its a daily driver, auto xsmn, 3.07 rear. I was considering a Scat cast 3.75 "internal balance" crank (has larger counterweights but has to use 6" rods), Scat stroker rods (6"), and a ZZ4 cam that a friend gave me from his crate engine. I have a set of alum. 58cc 113 heads that will be mildly ported, an accel intake manifold, LPE large tube runners, and a mildly ported plenum. I will have the block decked for better quench, but I am undecided on pistons and need to choose these first. I was looking at Wiseco forged dished ones, but they are a bit expensive. Can I go with a good set of cast ones to save a little cash? What are the pro's and con's of each? (forged vs cast). This car will never see the track or rpm beyond 5500.




The 58 cc heads are really going to push the compression ratio up there with a 383. I would check the compression and DCR with the pistons and cam to make sure you will be happy if this is a street car.

I just put some keith black hypereutectic (KB121) in a 383. They have a 28 cc dish and would put you at about 9.3 static compression with those heads which I would guess would be pretty good on 91 octane and maybe a lower octane. I couldn't figure the DCR as I don't know the specs on that cam. I think some of the guys on here don't like the KB pistons, but can't remember why.

I'll be interested in Grumpy's reply myself.

c ya,

Sum

DCR Combinations That Have Worked

1FATGMC Lakester Construction


 
63ss409 
Member
Posts: 20

Reg: 02-13-03
Re: building a 383, things to think about
11-25-06 02:38 AM - Post#932327    
    In response to 1FATGMC

I know I will have to compute the DCR correctly with these 58cc heads. I just need some input on which style of piston would be better for this street driven car. I know the forged pistons will rattle a bit until they get up to operating temperature. The cast ones can be fitted with smaller clearances, but I also have heard some negative comments on the KB hyper's. Considering this is going to be a "mild" 383, I figured the forged ones may be a bit of overkill and expense. I have another block that I'm going to use, so I can take my time. The original engine in the car still runs well, but has excessive leakdown in #6 and blows air out the dipstick tube during the test.



 
grumpyvette 
Senior Chevytalk Moderator -- Performance Subject Matter Expert --
Posts: 17142
grumpyvette
Age: 70
Loc: FLORIDA USA
Reg: 03-16-01
Re: building a 383, things to think about
12-30-06 03:16 PM - Post#932328    
    In response to 63ss409

on a street car its a good idea to hedge your bets and not run on the ragged edge of potential destruction, ID suggest staying UNDER 10.5:1 static and 8:1 dynamic CPR and keeping the quench in the .038-.045 range, coolant temps under 200F and the correct heat range plugs while useing HIGH TEST FUEL,(92-93 octane)
you can make decent power with a static cpr between 9:1 and 10:1 if you get the matching components.
If you can,t get that octane, either use a fuel booster, cut your cpr or retard the ignition curve, and richen the a/f mix slightly to cool the cylinder burn temp under high loads.
while Ive always PREFERED forged pistons due to the fact that they tend to absorb heat/detonation longer before failing, theres nothing wrong with hypereutectic pistons provided you realize the limitations, example
I built a 10.2:1 cpr 383 with KB hypereutectic pistons a few years ago and it KICKED BUTT, made about 420hp/450 tq and had a guys nova running consistant 13.20s with a stock trans and 3.08:1 gear and skinny tires,he did that for several years UNTILL one day when he advanced the timing about 5 degrees at the local track, thinking that adding a couple gallons of race gas to his nearly full tank of fuel would protect the engine,... IT DIDN,T ...and HE MELTED two pistons,.... broke rings and cracked both heads with the busted ring lands getting compressed between the heads and pistons.
we REBUILT the engine useing FORGED pistons, and hes more careful about the ignition curve and fuel, theres no real differance in performance, just a slight edge in durrability



 
grumpyvette 
Senior Chevytalk Moderator -- Performance Subject Matter Expert --
Posts: 17142
grumpyvette
Age: 70
Loc: FLORIDA USA
Reg: 03-16-01
Re: building a 383, things to think about
12-31-06 05:01 AM - Post#932329    
    In response to grumpyvette








 
72vega 
Senior Member
Posts: 481
72vega
Loc: Erie PA
Reg: 11-24-01
Re: building a 383, things to think about
01-01-07 06:30 PM - Post#932330    
    In response to grumpyvette

alot of great info, answered most of my questions.. but what if someone wanted to build a supercharged 383 using a centrifugal Procharger? what pistions do i use? i know i need dished pistons, but who makes one for a use like that? im not finding much for dished 383 pistons, maybey im looking in the wrong place.



 
grumpyvette 
Senior Chevytalk Moderator -- Performance Subject Matter Expert --
Posts: 17142
grumpyvette
Age: 70
Loc: FLORIDA USA
Reg: 03-16-01
Re: building a 383, things to think about
01-02-07 04:41 AM - Post#932331    
    In response to 72vega

http://www.jepistons.com/cat/je/auto/chevy_sb/extreme_duty_23_inv.shtml

I don,t build many supercharged engines but heres what I would sellect (part # 131631)



 
KsKustoms 
Member
Posts: 69

Loc: CA
Reg: 01-14-05
Re: building a 383, things to think about
01-02-07 11:56 AM - Post#932332    
    In response to 72vega

JE/SRP Pistons can be ordered with any SCAT rotating Assembly. I would say that if you want to use any forced induction or Nitrous then get the forged pistons. They do make them in all kinds of different dish cc's.

When was Too Much Power a Problem?
Check out the KsKustom Forum on CT


 
grumpyvette 
Senior Chevytalk Moderator -- Performance Subject Matter Expert --
Posts: 17142
grumpyvette
Age: 70
Loc: FLORIDA USA
Reg: 03-16-01
01-29-07 07:24 AM - Post#1082681    
    In response to KsKustoms

when you get to tunning it?

http://www.bob2000.com/carb.htm

http://www.mortec.com/carbtip1.htm

http://store.summitracing.com/partde...5&autov...
(buy two sets)

http://www.racingsecrets.com/article_racing-13.htm...

http://www.centuryperformance.com/vacuum.asp

http://www.centuryperformance.com/fuel.asp

http://www.goldrush.com/~rhuish/temp_data/car btune...

http://www.bgsoflex.com/holley.html


heres A/F

http://www.rbracing-rsr.com/rsrgauge.htm

http://www.mummbrothers.com/SRF_Stuf...e/Air_Fuel....

http://www.airfuelmeter.com/english/

http://www.innovatemotorsports.com/products/lm1.ph...

http://thedynoshop.net/prod01.htm

http://www.dawesdevices.com/airfuelmeter.html

http://fastrides.com/articles/DoItYo...tio_Gauge.h...

http://www.fuelairspark.com/Products...rFuelMeter....

http://www.3barracing.com/product_3.htm


a few places to look for more info on plugs


»http://www.acdelco.com/html/pi_plugs_ident.htm«



»http://members.uia.net/pkelley2/sparkplugrea ding.html

http://www.atlanticjetsports.com/_techtalk/0000000...

http://www.strappe.com/plugs.html«

»http://www.babcox.com/editorial/cm/cm59910.htm

http://www.ngksparkplugs.com/techinfo/spark_plugs/ ...

»http://www.nightrider.com/biketech/spkplghnbook .htm

http://www.tsrsoftware.com/sparkplug.htm



»http://www.dansmc.com/sparkplugs1.htm«

»http://www.ngksparkplugs.com/techinfo/spark_plugs/ overviewp2.asp«

»http://www.centuryperformance.com/spark.asp

http://www.edelbrock.com/automotive/sparkplugs .htm...


»http://www.powerarc.com/sparkplug.htm

http://www.carcraft.com/techarticles/64378/

http://dodgeram.org/tech/gas/spark_plugs/ s_plug_fa...

»http://www.centuryperformance.com/spark.asp

http://www.powerarc.com/sparkplug.htm

http://www.edelbrock.com/automotive/sparkplugs .htm...

http://www.answers.com/topic/spark-plug


IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!


Edited by grumpyvette on 01-29-07 07:30 AM. Reason for edit: No reason given.

 
mylesdw 
Member
Posts: 1

Reg: 03-12-07
03-22-07 07:30 PM - Post#1126251    
    In response to grumpyvette

The SBC in my car is an early 327 fitted with a 350 crank turned down to suit the small journal block. Is there any reason why I can't fit a 3.75" crank by turning down the mains in the same way? The plan would be to keep the large journal big-ends and add 6" rods and hypereutectic (sp?) pistons. Any idea if this will yield particular clearance or balance issues?

Cheers
Myles




 




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