Q: I have a 1963 Chevy II that I am fixing up. It has a 350 small block bored .030-inch over with a 383 stroker crankshaft, 5.7-inch connecting rods, and forged flat top pistons that spec out to 11:1 compression with 64cc heads. However, the heads I used are 58cc camelback heads that were supposedly rebuilt with the largest-sized valves possible. The engine also has a 480-inch lift Lunati Bracket Master cam, Edelbrock 750 cfm carburetor, Edelbrock Performer intake, Mallory distributor and Promaster coil, and Hooker 1 7/8-inch primary headers. The transmission is a Turbo 350 with a 3,000-3,500 rpm stall TCI converter. The rear axle is a Ford 9-inch with 4.11 gears.

The car does not perform as well as I expected it to. It runs kind of rough and won’t do a burnout very easily. Do you have any tips or suggestions on how best to time or tune the engine for better performance?

A: Your parts combination sounds good, but our first question concerns the cam—did you degree it when you installed it? It should have been installed “straight up” (not advanced or retarded) at zero degrees. The rocker arms should be set at zero lash with an additional quarter-turn to tighten.

The second concern is the cylinder heads. With that small 58cc combustion chamber and what you say are the large valves, the valves may not be properly unshrouded. If that is the case, airflow into the cylinders will be restricted, which can cause the sluggishness and lack of power you are experiencing.

You will have to play with the ignition timing to see what the 350 likes. 36-38 degrees total advance at 2,500 rpm is a good starting point. Increase timing by two degrees until you hear detonation, then back off by two degrees. You will need to dial in the carburetor for optimum performance. Edelbrock makes a Calibration Kit that will help you do this.

With as much compression as you have, you might think about changing from the Edelbrock dual-plane intake to a single plane. An Edelbrock Victor Jr. would be a good choice.

This is another in a series of weekly Q&A Mailbag sessions with Summit Racing‘s tech department, in which there are hundreds more. Click here to see them all

 

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