Hey Ken – way too many unknowns here.

Are your 335 heads the 121cc or 114 cc combustion chambers?

What is the deck height? Most big blocks are 9.800 – 9.820 stock and true zero is 9.78. Was your block decked before build?

What cam are you running?

Recommended gasket with these heads is .039. Thinner is not good – definitely not the way to increase compression especially with a true flat top piston where clearance may be tight already unless you want the valves to perform a custom fly-cut in those flat tops!

These heads perform best in the 3,000-7,000 rpm range. What is your RPM through the traps?

Did you build or buy this engine? To get those kind of numbers one needs to invest well north of $10K - and I mean well north.

Did you see the dyno run? Do you have the dyno printout? I’m not busting your chops, but something just doesn’t sound right to me.

Your buddy is right – weights of the two cars are close. In raw terms, assume 10 gallons of gas and 200 pound driver, the calculated ET for these two are as follows:

Chevelle weight: 3800
Flywheel Horsepower: 649
60 Foot Elapsed Time = 1.6
1/8 Mile Elapsed Time = 7.01
1/4 Mile Elapsed Time = 11.04
1/4 Mile Trap Speed = 136.52

For the Camaro to beat you by two or three car lengths in a quarter your buddy’s car would been to be pushing 700 horsepower.

Camaro weight: 3750
Flywheel Horsepower: 700
60 Foot Elapsed Time = 1.52
1/8 Mile Elapsed Time = 6.80
1/4 Mile Elapsed Time = 10.71
1/4 Mile Trap Speed = 140.62

Give us a bit more information.

Best,
Glenn