VetteRed1965
Forum Newbie
Posts: 6
Loc: Woodstock,Georgia
Reg: 05-06-12
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05-06-12 06:31 AM - Post#2223025
My heads are overhauled with new 2.02 and 1.60 valves with screw in studs. The combustion area is calculated to be 64.4 cc's. Hydrolic lifters.
The machine shop says to use a head gasket with a compression of .35 to achieve a compression of 10.1 to 10.5. On another forum they say that I'm leaving a lot of HP on the table with the cam selected.
Any help apreciated ! I will be assembly of the heads and components starting next week !
Here are the specs for the block and cam below. Thx VetteRed
Block
Deck -.003
bore 4.030
stroke 3.250
CID 331.6
Pistons TRW 4 valve reliefs piston to cyl wall .0032
Cam Elgin Prostock E1011P
Cam Lift
Int .325 Exh .325
Valve lift
Int .488. Exh .488
Lobe centers
Int 106 Exh 110
Adv Dur
Int.292 Exh 300
.050 Dur
232int 234 Exh
Adv.timing
BTC-39 ABC-73 BBC-79 ATC-41
.050 Timing
BTC-10 ABC-42 BBC-47 ATC-7
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 MikeB
Senior Member
Posts: 9388
Loc: Plano, TX
Reg: 08-28-03
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05-06-12 08:24 AM - Post#2223066
In response to VetteRed1965
How do you plan to use the car?
Which heads?
What does it weigh?
What are transmission type and axle ratio?
Real Hot Rods have a Clutch!
1955 210 2dr: 327, Brodix IK180 heads, Jones cam, Muncie M20, Wilwood front brakes
1969 C-10 pickup: 350, TH350
My car pictures
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Edited by MikeB on 05-06-12 08:26 AM. Reason for edit: No reason given.
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 grumpyvette
Senior Chevytalk Moderator -- Performance Subject Matter Expert --
Posts: 15639
Age: 65
Loc: FLORIDA USA
Reg: 03-16-01
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05-06-12 08:35 AM - Post#2223070
In response to MikeB
his posted car info
weight 3230
tires 205 75R15
axle ratio 335
4 speed
if IT was my car, ID stick a crane 110931 solid lifter cam and 1.6:1 ratio roller rockers on the car(keep in mind the rpm band in a 327 will be higher than shown which assumes a 350-383 displacement as those are currently more common displacements)
while its true a larger cam would produce more peak hp, your rear gears not ideal for racing,and better matches the milder cam I linked too, this is a street car that will spend a good deal of its time at lower than peak rpms
if it was strictly used for racing a cam like a crower 00355 and a 4.56:1 rear gear ratio might be used, don,t make the mistake of caming the car for max power when youll spend 5% of your time at peak rpms, youll be happier caming the car for where you spend 95% of your time
| " " IF YOU CAN'T SMOKE THE TIRES FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK !" |
Edited by grumpyvette on 05-06-12 08:49 AM. Reason for edit: No reason given.
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MikeB
Senior Member
Posts: 9388
Loc: Plano, TX
Reg: 08-28-03
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05-06-12 03:27 PM - Post#2223189
In response to grumpyvette
I've built maybe 1/10 the engines Grumpy has, but I wouldn't exceed 220 duration @.050". Even the old 350hp/327 cam (221/221) was typically used with a 3.73 axle.
In fact I'd probably be looking for something around 210-216 duration. Anything bigger will take away from low-mid RPM torque to make more high RPM horsepower. If this is mainly a street-driven car, your engine will spend most of its time well below 4500 RPM.
Is your deck at .003" or -.003"? At .003" a standard .038" gasket will work. If it's -.003" that would make quench height only .035". I guess that's OK, but a little close for me.
Is axle ratio 3.35 or 3.55?
Real Hot Rods have a Clutch!
1955 210 2dr: 327, Brodix IK180 heads, Jones cam, Muncie M20, Wilwood front brakes
1969 C-10 pickup: 350, TH350
My car pictures
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Edited by MikeB on 05-06-12 03:32 PM. Reason for edit: No reason given.
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VetteRed1965
Forum Newbie
Posts: 6
Loc: Woodstock,Georgia
Reg: 05-06-12
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05-06-12 05:49 PM - Post#2223231
In response to MikeB
deck is at -003
axle I believe is a 335. At 70 mph the tach
reads 2900.The cam is already installed. It looks
like I need to save more money to buy a different cam.
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rumrumm
"12th Year" Silver Supporting Member
Posts: 1784
Loc: Macomb, IL
Reg: 10-18-01
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05-07-12 05:51 AM - Post#2223364
In response to VetteRed1965
If this is a street car and not strictly a strip car, your cam is huge. I agree with MikeB on this. The cam you have is better suited to a street driven 383 than a 327. I also have doubts that your heads could provide the air flow needed to make that big cam work effectively unless you have done a great deal of port work to them.
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grumpyvette
Senior Chevytalk Moderator -- Performance Subject Matter Expert --
Posts: 15639
Age: 65
Loc: FLORIDA USA
Reg: 03-16-01
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05-07-12 06:23 AM - Post#2223370
In response to rumrumm
I got a few emails asking why I suggested the crane cam I posted, every choice is a compromise the key is selecting a decent match,first keep in mind this is a 327 with a manual transmission, and close to 9.8:1 compression, the engines piston speed doesn't get to be a factor until about 7000rpm plus so its silly to restrict the engine with a hydraulic lifter cam that will not function well over about 6200rpm
IF WE LOOK AT THE DISPLACEMENT to VALVE SIZE we get 20cid so a 110 LSA is about correct
IF we want to be a bit CONSERVATIVE on duration because this is a street application and calculate BOTH dynamic compression to fall near 8:1 to allow crappy octane fuel and enough duration to allow restrictive heads to breath at mid and upper rpms we find your looking at 220-230 degrees of intake duration, adding extra exhaust duration tends to compensate for a restrictive exhaust most corvettes with mufflers are equipped with. while its very true that a 215 duration cam would increase the low and mid rpm torque it would run out of breath far sooner, again restricting the 327 engines potential strong point, its ability to easily spin 6500-7000rpm (with a cam thats designed to allow it too!)even a 228 intake duration is a compromise in this area, but it matches the combo well when trying to get the correct dynamic compression
POST SPEED WILL ALSO LIMIT A CAM WITH LESS THAN ABOUT 225 duration and having over .500 lift will help, hence the reference to the crane cam and 1.6:1 ratio rockers
http://forum.grumpysperformance.com/viewtopic.php?...
http://forum.grumpysperformance.com/viewtopic.php?...
lets look at the potential difference in two cams similar to what are suggested
HERES a cam with 216 intake duration
heres the result of the same engine with just the rockers and cam slightly larger
| " " IF YOU CAN'T SMOKE THE TIRES FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK !" |
Edited by grumpyvette on 05-07-12 10:16 AM. Reason for edit: No reason given.
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VetteRed1965
Forum Newbie
Posts: 6
Loc: Woodstock,Georgia
Reg: 05-06-12
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05-07-12 02:24 PM - Post#2223486
In response to grumpyvette
Well...I spoke with the machine shop about the cam being to big. He said he would swap it out if it did not perform to expectation's. He said that he did some interior stuff to the block and heads. I knew he ported,matched and flowed the heads. .He said it would come alive at 2000 thru 6500 rpm's. He sponsored a friend's car at road atlanta who was no.1 in the vintage series for 15 years... He said if I did not like the performance that he would swap out the cam. I trust this guy and hopfully have a great engine. 
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MikeB
Senior Member
Posts: 9388
Loc: Plano, TX
Reg: 08-28-03
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05-07-12 02:53 PM - Post#2223491
In response to VetteRed1965
its silly to restrict the engine with a hydraulic lifter cam that will not function well over about 6200rpm
Good point. He's got a 7000 RPM cam with 6000 RPM lifters.
He said it would come alive at 2000 thru 6500 rpm's.
2000 is a bit optimistic. My 55 sedan's 327 used to a have a 224/230 solid lifter cam, and 2000 RPM is about where it started to make usable power. Also, be prepared to deal with not being able to adjust idle mixture, as well as poor manners on the street, including surging at low RPM. And I hope you don't have any vacuum controlled accessories. I'm just sayin'... 
Real Hot Rods have a Clutch!
1955 210 2dr: 327, Brodix IK180 heads, Jones cam, Muncie M20, Wilwood front brakes
1969 C-10 pickup: 350, TH350
My car pictures
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Edited by MikeB on 05-07-12 02:55 PM. Reason for edit: No reason given.
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