You’ve got questions. We’ve got the answers—the Summit Racing tech department tackles your automotive-related conundrums. This week, we’re helping a reader dial back the performance of his 454 for street use.
Q: I have a second-gen. Camaro Z28 with a 1976 454 bored .030 inches over. The car has the following parts:
- Stock crank, rods, and TRW flat-top pistons
- 1968 “.063” casting closed chamber heads with 2.065-inch/1.72-inch valves. Bronze valve guides, roller tip rocker arms, ported matched on intake and exhaust sides (I also have the original 1976 “781” casting heads)
- Hydraulic cam with 245/255-degree duration at .050, .585-inch lift
- Edelbrock Torker intake with a 925 cfm Holley double pumper carburetor
- Mallory Unilite distributor (no vacuum advance), Promaster coil, MSD 6AL box
- Hooker Competition headers with 2.25-inch dual exhaust
- Turbo 400 transmission with shift kit and 4,500 stall converter
- 10-bolt posi rear axle with 3.42 gears and 26-inch tall tires
I am going to rebuild the engine and would like your opinion on any changes that would make the car more streetable. I know the current combo is not very streetable. I will not change the rear axle gears.A.K. Moberly, MO
A: The least expensive way to detune your engine for the street is to use the 781 casting heads with TRW-L2399F domed pistons. This combination will give you around 9.3:1 compression. You should also go to a cam with a 235 duration @ .050-inch lift and get a torque converter that stalls around 2,500 rpm. These changes will make the Camaro more driveable and allow the use of pump gas.