1969 SS Chevelle. .040 over 396(404), 9.6:1, 268H, 650 spreadbore DP, Pertronix & Flamethrower, chambered exhaust, 2400 stall, 3.42:1. Fresh, balanced, runs perfect. Need tuning advice (initial timing, etc.) for best performance. Thanks.

mrhp,I HAVE A 69/396 (NOW 402) WITH A COMP CAM 268H TOO. IT RUNNING THE STOCK INTAKE,Q-JET,FLOWMASTERS,STOCK EX MANIFOLDS,12 BOLT (OPT 307 GEAR/YUK),4SPD.

OOppSS,sorry about the caps lock.

Anyway,on any mild to hot perf cam you generally need to run approx 16-18 deg btdc intial adavance not including your mechanical and vacuum advance too. You can NEVER use the stock GM timing specs on an aftermarket perf cam becasue they will cause you to be way too far retartded. This will cause your motor to have all sorts of issues like running hotter,unstable idle,very low end power,terrible throttle responce,lower than normal idle vacuum affecting your carbs power valve and possibly your power brakes,etc.

I found through dialing in my car that 18 deg btdc was where my initial timing needed to be with my vacuum advance hose attached to the ported carb vacuuum source.

I hope this helps you out.

Scott