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AM I OVER CAMMED? COMP CAMS 294H (12-254-3)
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lazr_guira
I love my Chevy Chevette!
| Posts: 1
| Joined: 10/09
Posted: 10/26/09 11:24 AM
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Hi all. I'm new to this forum and have a few questions. Is any body running a a comp cams 294H (12-254-3) ? I bought one and i think the cam maybe a little to big for my application now. Its not like i didn't take the time to reserch the cam a little. even on the comp cams website thier dyno sheet is almost 100% the same as mine exept for the 1 3/4 headers. Mine are have 1 5/8.
http://www.compcams.com/technical/Dy...94H-10_001.asp
I feel like my setup is making more like 325HP not even close to what it should be. what did i do wrong?
any way i was expecting my 1980 camaro to run low to mid 12's and the best i got was 13.14 @103 mph.
here is my setup WORLD PRODUCTS FULLY PORTED SPORTMAN II MANLEY SERVERE DUTY VALVES 2.02 X 1.6 (STOCK LENGTH) VICTOR JR (FULLY PORTED) MAGNUM 1.6 ROLLER ROCKERS STOCK BOTTOM END WITH 9:1 TO 9:5 COMPRESSION HOLLEY 750 DOMINATER (MAYBE A LITTLE TO BIG) COMP CAMS 294H (12-254-3) TURBO 400 W/TRANS BRAKE B&M HOLE SHOT 3000 ( LEAVING AT 3400 ON THE BRAKE) I know wrong converter for a brake. 4:10 gears 28" MICKY DRAG RADIALS CALTRACS MSD 6AL-2 W/ PRO BILLET DIST.
car wieghs 3690 with me in it and 3450 empty. any help or advise will be greatly appeciated. Thanks
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Pontiacman2
Everything in my driveway’s a Chevy
| Posts: 669
| Joined: 01/08
Posted: 10/26/09 02:14 PM
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Your Cr should be higher to match the cam and intake but I would try a different intake like the weiand air strike or edelbrock rpm air gap.
Professional hi-performance engine builder
Horsepower sells Engines and torque wins races.
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OldCrLvr
I love my Chevy Chevette!
| Posts: 16
| Joined: 03/09
Posted: 10/31/09 10:52 PM
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Neither the comp dyno software nor the website give a compression ratio range for your cam. But looking at similar cams they sell like the the 292 requires at least 10:1 and the 296 requires your compression to be at least 10.5. I'm thinking that you just plain need more compression.
1963 Chevy II SS 1970 C10 1971 Chevelle Malibu 2000 Z71 2005 Passat 4Motion
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85_trans_am
My first time was in a Chevy
| Posts: 240
| Joined: 05/09
Posted: 11/01/09 05:35 AM
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sounds to me like you have a lot is this one. I would recomend 1 of 2 things. 1. rebuild the bottom end to match the top end or 2. find a supercharger kit and bolt it on to make up for the bottom end.
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OldCrLvr
I love my Chevy Chevette!
| Posts: 16
| Joined: 03/09
Posted: 11/01/09 02:55 PM
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I did a bit more reaserch: Trying to figure out what your real compression ratio was, here is what I assumed: Plane old 350 4 valve relief pistons seem to have about a negitive impact on compression of about 6cc. I also guessed it's a 4.030 overbore and the pistons are in the hole about .016". Assuming you went with generic FelPro SBC gaskets they have a 4.125 bore and are a compressed thickness of .039." Now, the World heads could either have 64 or 72cc combustion chambers. If you have 64cc heads your compression is approx 9.93:1, which is good of course. If you have 72cc you should be about 9.13:1. If you do have the 72cc heads and want to increase your compression easily you could swap out heads gaskets. By getting a smaller bore and thickness gasket like Summit Racings P/N:SUM-111500 which has a compressed thickness of .032 and bore of 4.060 that would bring you up to 9.3:1. If you could mill the heads, every .006" you take off is a cc. I'm not sure how much you can mill before you get alignment issues with the intake. Lets say you milled it .012" your new ratio would be 9.49:1 (that is on top of the different gaskets).
In the example you gave from Comp Cams they only had 9.25:1 with their test engine and it made 415HP & 394FtLb. Using their dyno/cam finder software the program guessed the power of your engine to have your torque and horsepower numbers well over 400. Another thing I did notice is that the program recommended a 3700lb car to have a torque converter in the range of 3400-4400.
1963 Chevy II SS 1970 C10 1971 Chevelle Malibu 2000 Z71 2005 Passat 4Motion
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ERIK427
I love my Chevy Chevette!
| Posts: 7
| Joined: 11/09
Posted: 11/05/09 09:09 AM
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Your compression is to low. Try using a thinner head gasket or mill the heads. Call world products on how much, you must be careful this does weaken the heads. Valve clearance is a issue too. Try a DEMON CARB. Use weaker springs in the distributer. And a hotter plug. I am led to think you have a 350 punched 30 over. If so your bore is a bit to small for your heads. Your intake is fine, make sure you gasket matched the heads to the intake. 11.1 compression or more is what you should have. Try smaller jets in the carb as well. Your carb is not to big, just not set up right? THERE I WAS NICE SUPER CHEVY!!!
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