 66SS632
"5th Year" Silver Supporting Member
Posts: 438
Loc: Langley BC
Reg: 02-09-13
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 12-17-22 10:54 PM - Post#2851390
So here’s a little bench racing quiz to add a little fun to the forum.You are obviously sitting in front of your computer (or device) and NOT working on your car!!
As I’m sure everyone is aware the price of gas this past summer was absolutely insane !
The price of Chevron 94 here in the Vancouver British Columbia Canada area reached a high of Cnd $2.76 a liter! That’s over $12 Canadian an imperial gallon!
Many of you know that I’m running a 632 CID big block Chevy in my car. It makes about 750 hp and 775 foot pounds of torque, as was proven on an engine Dyno.
The engine has a 1050 Dominator carburetor and on a good day I’ll maybe get 6 or 7 miles per gallon. At 12 bucks Canadian a gallon it can get pretty expensive to drive the car! Not complaining course LOL! We all know that it cost money to drive these cars but it is getting pretty expensive to say the least. It’s nice having all that power on tap, but Street racing is out of a question these days and we’re settling into the “cruising around" and “car show” phase of our empty nest existence lol! I have struggled (emotionally ) with the plan to "downsize" the horsepower because it REALLY is addictive, but I think I can deal with it short term. I've got an LS core that is begging for my attention. I'll bring myself into the 21st century eventually!
So I decided to rebuild my 454 that was in the car previously. I could squeeze 12 miles per gallon or maybe more if I was nice to it. It was by no means a slouch as I estimate it 500+ hp. I was going to install it last summer but never had the opportunity as the time crunch and the unexpected delays in getting parts. As I’m sure most of you are aware there are supply chain issues. Cam regrind took almost 6 weeks and there was NOTHING available locally in the profile I wanted.
So I tore the engine down and decided the bearings were good so I reused them but I honed the bore , added new piston rings and a new cam shaft and lifters .The camshaft that was in the engine was a mechanical roller so I had it re -ground to a similar grind but with a hydraulic roller profile.
I fired up the engine on my test stand just to break it in, but never installed it in the car and never Dyno tested it. By the time the engine was ready it was less than a week before we were scheduled to go out of town to a car show. I really didn't have time for a swap. It’s been sitting in the back of my shop since the summertime.
So next week it’s scheduled for a Dyno session to see how much Power it makes. Here are the specs;
-454 bored .030 over with small dome pistons, about 11.2 :1 CR
-hydraulic roller camshaft with 0.636 lift and 276 and 284 @ 0.050 on 110 lobe separation angle
-heads are ported and polished “Z16” Casting # 3856208 . These are the heads that came on the 425 hp 427 and 396 in 1965-66. They’ve been freshened up with new seals and valve springs and valve grind
Dominator open plenum intake with a 750 cfm Dominator carb. Also have a 950 CFM Holley on an adapter plate(4150 to 4500) that I want to try
Sooooo
How much power is it gonna make?
I’m thinking 525 hp and 540 ft/lbs torque.
Don’t be shy! Chime in!!
What do you think?
Scheduled for dyno test on Friday. I’ll post it next week after the Dyno test! 
Still a 17 year old delinquent Hot Rodder
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 Shepherd
Valued Contributor
Posts: 2849
Loc: Lake George, NY
Reg: 11-11-15
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12-18-22 07:00 AM - Post#2851399
In response to 66SS632
Pretty big cam in that engine, that said, I would think a properly tuned 800-850 carb would improve peak power. Those heads were good in the day, but modern aluminum heads would be a huge improvement. I'd guess 525 would not be an unreasonable figure.
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 DHMelton
Silver Supporting Member
Posts: 163
Loc: Central Arizona
Reg: 04-10-22
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12-18-22 09:06 AM - Post#2851405
In response to Shepherd
Dunno how much power it will make but you can get a "lot" better mileage on either engine.
Some may not realize the following as truths, but they are:
-- CI displacement has almost no bearing on gas mileage as a steady state speed. Larger engines have a bit more friction loses and cooling system heat rejection, but a large motor only uses as much fuel as necessary to make the HP (which is constant, large or small motor) to move a car down the road.
Steady state HP depends on rolling friction and air resistance, motor size has nothing to do with it.
You are shooting yourself in the foot with that 110 LSA cam. You would be much better off running cam with a 112-114 LSA. The 106 is fine if you are spending all your time over 5K RPM, not so much for the street.
I have a 427 CI small block in my 1961 Corvette, yes its only a 3000 lb car, but it gets over 20 MPG at 60 MPH and has more average HP under the HP curve than an old L88 motor has, and I have a ~9:1 compression ration and 113* LSA Hdy roller cam.
It is "very" tame until you open the throttle, unlike a lumpy L88 motor with its flat tappet cam and 12:1 CR
On the chassis dyno (rear wheels), it has 400 ft-lb of tq at 1700 RPM, and will run to over 6500 RPM, but the power falls off over 5500 RPM, so running faster is pointless. The car is quick. It runs mid 12s @ 117 MPH with a slow shifting DNE 5 speed on street tires; slicks and an automatic would put it into the low 11s.
One thing that helped power and mileage was programmable port EFI built on a Vic Jr manifold. And it all fits under the hood of the car, a taller manifold would extend the RPM range by 500 RPM or so, but it won't fit under the hood.
I will be using similar wide LSA cam in the 479 CI BB I am now building (3.76" stroke, 4.500" bore) with 9.6:1 CR
I will post a pic of the Tq curve in a separate post.
Doug
Edit: corrected LSA angle info on OPs cam, dunno where I saw 106.
Edited by DHMelton on 12-18-22 01:50 PM. Reason for edit: No reason given.
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DHMelton
Silver Supporting Member
Posts: 163
Loc: Central Arizona
Reg: 04-10-22
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12-19-22 12:51 PM - Post#2851447
In response to DHMelton
Couple otehr things:
Make sure your dizzy vac can matches the idle vacuum (can connected) fully engaged about 2" below idle vacuum, and your centrifugal advance is all in by around 3000 RPM.
The MR Gasket Gold springs that come in their spring curve kit are pretty close to 3K RPM, but do NOT use the Mr Gasket advance weights, use the factory weights.
Thats all I can think of other than primary jetting on your carb, the factory holley jets are real rich to help with narrow LSA high overlap cams and exh gas reversion narrow LSA causes.
You can get close to an EFI tune (at one altitude), just dialing in the distributor and carb jets,and accel pump, it just a lot more trial and error that takes longer.
Doug
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66SS632
"5th Year" Silver Supporting Member
Posts: 438
Loc: Langley BC
Reg: 02-09-13
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12-19-22 02:06 PM - Post#2851455
In response to DHMelton
The cam in the 454 has 110 lobe separation angle not 106.
I’m wondering on what basis you’re saying that 110 degree lobe separation angle is “shooting myself in the foot” ? Is this from many years experience building engines? It’s a done deal now so it’s sort of irrelevant!!
The cam I took out of 454 originally was an old Erson grind mechanical roller. The lobes were showing signs of wear so I decided to replace it. The Engine pulled hard from 3500to 6000 so I know it was working well in this application.
A local cam grinder with years of experience suggested the profile that I decided on. It was very similar to the original grind except hydraulic roller profile. Target is mid range torque and peak power in the 5500 range. I’m confident this thing will make over 500 hp. The previous owner of my car was running mid 12’s @ 112 with time slips to prove it.
The fuel consumption between the 632 and the 454 is dramatic!
The bore and stroke on the 632 is 4.620x 4.750 vs the 454 which is (0.030 over) 4.280x 4.00.
You stated:
- CI displacement has almost no bearing on gas mileage as a steady state speed. Larger engines have a bit more friction loses and cooling system heat rejection, but a large motor only uses as much fuel as necessary to make the HP (which is constant, large or small motor) to move a car down the road.
Having had both engines in the car with the same transmission, same rear end ratio, tuned with an air fuel ratio gauge that it definitely does have bearing on fuel consumption! Difference of 6 mpg as a matter of fact!
Theory and reality often don’t agree. Even highway driving most of the time you can’t maintain a “steady state”. That sounds like EPA logic.
I get the so much power to move at specific speed but fuel consumption is going to vary with a 27% difference in CID!!
I drove the car the same way with both engines. Sometimes polite, other times not. A tank of gas would always last longer with the 454.
My Impala weighs in probably over 4500 lbs without me in it. When I weighed it when I first bought it the scale said 4250 . Since then there is a Dana 60 , extra steel on the frame and various other heavy parts. Definitely a factor for MPG.
Fuel injection would definitely help fuel efficiency and power. It’s been a while since I looked into available kits, but I noticed most throttle body systems max at 650-700 hp. Maybe different now. My choice for the 632 would be port injection but tall deck port systems start around $4500. I would rather spend that modernizing to an LS application.
This post is for fun, result by the end of the week. I’m quite excited about it!
Take a guess. We’ll see what happens.
Still a 17 year old delinquent Hot Rodder
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DHMelton
Silver Supporting Member
Posts: 163
Loc: Central Arizona
Reg: 04-10-22
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12-19-22 03:36 PM - Post#2851460
In response to 66SS632
I thought I edited the shoot/foot out, sorry, somehow, i thought i read you had 106* on the 454, not 110*.
What LSA do you have on that 632?
That 1050 Dominator just won't deliver optimum fuel economy, regardless.
As far as displacement vs fuel economy.
At steady state, lets say you need 40 HP to keep the car rolling on flat ground at 60 MPH.
You need 40HP whether its 200 CU, or 632 CI.
Both engines will put just as much HP as needed (40), no more, no less. HP= BTU= lbs fuel/min, so both engines would get the same MPG if they have the same AFR.
And the same cam profile.
a 200 CI motor with a mild cam and 116* LSA won't pump unburned gas out the exh at 2000 RPM, whereas a 106" LSA motor will pump unburned gas out at 2000 RPM, killing economy.
I am ignoring the extra ring friction of the larger motor for that comparison.
Lets see, you have 11:1 CR (approx), CR is very close to linear to torque output (and thus HP),
so a 454 11:1 CR motor being equal to a 9:1 CR 454 motor would put out about 20% more Tq/HP than a 9:1 motor.
But, you have different heads that i do, I do not know what the flow bench numbers on the heads are, so that is where your HP will be made, or not.
http://users.erols.com/srweiss/tablehdc.htm#Chevy_...
You are probably close at 550 HP at around 6K RPM, the intake and cam duration is a bit much for under 3000 RPM use, I am going to say your 2000 RPM torque is 100 ft lbs. Maybe 300 ft-lbs at 2500 RPM, 400 lt-lbs at 3000 RPM then climbing fairly quickly to peak at 5000-5500 RPM.
That is with open headers.
Good luck!
Doug
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65cayne
Contributor
Posts: 142
Reg: 08-21-07
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12-23-22 09:35 AM - Post#2851556
In response to 66SS632
Is this correct?
276 and 284 @ 0.050 on 110 lobe separation angle
If so, that is one of the biggest cams I have ever seen and while I don't know where peak power will be, it's not gonna be at ~5500rpm like you desire/stated.
For reference, my 10:1 454(+.030) with a 229/241@.050 on a 109 LSA makes ~560 peak horse power right about 6000 rpm and ~578 lb-ft peak torque at 4000-4100 rpm.
What are your goals for the engine as far as usage?
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DHMelton
Silver Supporting Member
Posts: 163
Loc: Central Arizona
Reg: 04-10-22
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12-23-22 01:22 PM - Post#2851565
In response to 65cayne
The engine runs out of breathing at about 5300 RPM witha 750 CFM carb, so the 750 carb would not allow any more HP beyond ~6K RPM, if the carb is increased, in size, power rises beyond 6500 RPM, but then the valves start to float, so the cam as originally stated would theoretically max out on HP way beyond 6500 RPM, but the intake or valve train won't let it.
Yes, those specs, if at .050" is way, way big on duration.
If those durations are at .006", then it's a fairly normal cam.
Edit: going to a 236/246 cam on 112 LSA would get about 530 HP at 5K RPM with open exhaust. That not necessarily the best cam choice (i just used it as an example), buts thats about what it would produce, with much higher torque at 2000 RPM vs the original specs listed.
Doug
Edited by DHMelton on 12-23-22 01:34 PM. Reason for edit: No reason given.
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65cayne
Contributor
Posts: 142
Reg: 08-21-07
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12-23-22 01:53 PM - Post#2851567
In response to DHMelton
The engine runs out of breathing at about 5300 RPM witha 750 CFM carb, so the 750 carb would not allow any more HP beyond ~6K RPM, if the carb is increased, in size, power rises beyond 6500 RPM, but then the valves start to float, so the cam as originally stated would theoretically max out on HP way beyond 6500 RPM, but the intake or valve train won't let it.
Yes, those specs, if at .050" is way, way big on duration.
If those durations are at .006", then it's a fairly normal cam.
Edit: going to a 236/246 cam on 112 LSA would get about 530 HP at 5K RPM with open exhaust. That not necessarily the best cam choice (i just used it as an example), buts thats about what it would produce, with much higher torque at 2000 RPM vs the original specs listed.
Doug
Are you referring to your engine or the OP?
I agree with you that the cam (if those .050 specs are correct) will make power far beyond where a BBC hydraulic valve train will carry it. And if built to support those RPM's, yes the 750 will hold it back significantly.
I cant even fathom a guess on the dyno because I've never seen a cam that big in a street engine. 
With 11.5 compression, and built properly, it should be over 600 hp.
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DHMelton
Silver Supporting Member
Posts: 163
Loc: Central Arizona
Reg: 04-10-22
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12-23-22 02:03 PM - Post#2851568
In response to 65cayne
The OPS 454 is what I am referring to in all of my above post.
Doug
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66SS632
"5th Year" Silver Supporting Member
Posts: 438
Loc: Langley BC
Reg: 02-09-13
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12-24-22 02:00 PM - Post#2851592
In response to 65cayne
Is this correct?
276 and 284 @ 0.050 on 110 lobe separation angle
If so, that is one of the biggest cams I have ever seen and while I don't know where peak power will be, it's not gonna be at ~5500rpm like you desire/stated.
For reference, my 10:1 454(+.030) with a 229/241@.050 on a 109 LSA makes ~560 peak horse power right about 6000 rpm and ~578 lb-ft peak torque at 4000-4100 rpm.
What are your goals for the engine as far as usage?
No I made a mistake there.
Advertised duration is quoted.
Anyway ,Dyno sessions went well. I’m quite pleased.
I’ll post the results and upload the video in a bit.
Still a 17 year old delinquent Hot Rodder
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66SS632
"5th Year" Silver Supporting Member
Posts: 438
Loc: Langley BC
Reg: 02-09-13
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12-25-22 04:35 PM - Post#2851623
In response to 66SS632
Here's the video.
Street motor. Tried 2 different carbs. Made the best pull with the 950 cfm (4150) on an adapter plate.
First pull with the 950 was really lean on the top end. Jetted it up a few and was better.
https://www.youtube.com/watch?v=G_KlXIJlC4A
Still a 17 year old delinquent Hot Rodder
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DHMelton
Silver Supporting Member
Posts: 163
Loc: Central Arizona
Reg: 04-10-22
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12-25-22 08:51 PM - Post#2851628
In response to 66SS632
Yeah, way lean on top end. 12.5:1 at WOT will get you another 25-30 HP.
Good job.
Doug
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DHMelton
Silver Supporting Member
Posts: 163
Loc: Central Arizona
Reg: 04-10-22
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12-25-22 08:56 PM - Post#2851629
In response to DHMelton
Did you have an air filter base on the carb during the pull, or just an open bare carb, no air cleaner base. (going by the pic)
An air filter base reduces inlet turbulence and helps HP. It should reduce your AFR reading, to my thinking.
Doug
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65cayne
Contributor
Posts: 142
Reg: 08-21-07
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12-28-22 08:54 AM - Post#2852924
In response to 66SS632
Here's the video.
Street motor. Tried 2 different carbs. Made the best pull with the 950 cfm (4150) on an adapter plate.
First pull with the 950 was really lean on the top end. Jetted it up a few and was better.
https://www.youtube.com/watch?v=G_KlXIJlC4A
531hp/541lb-ft looks like your original guess was right on the money. Nice job on hitting your number! Always a good feeling.
Agree with the above on fattening up the mixture. Curious what the next pull produced after re-jetting.
A few questions... what is the .050 duration on that cam? It looks small for an 11.2:1 engine. Your cranking compression must be well over 200psi unless you retarded the cam.
Given your numbers on the dyno sheet, have you considered a dual plane manifold?
Not knocking your build at all. I think it's going to perform quite well in your car and I enjoy getting other's perspective on how they brought their combo together. Always looking to learn something. BTW it sounded great grunting on the dyno!
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