Stop in for a cup of coffee

71GSSDemon said

Mark, what timing do you run in your ride?


The boys car is 1931 Model A sedan with 460 C6 and 9" (3.55). This spring we changed to closed chamber DOVE heads for a nice bump in compression and a Comp Cam Thumpr cam. Everything I have read says they like 12-14° at idle which seems low on the Mopar side of things. I can try richening it up. It has and Edelbrock AVS2 from his grandpa on it @Just Ron but I don't know much about them other than the idle adjustments on the front.

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I agree seems like not enough initial, but its a big engine. Do you know the cam duration?
Can look at the Barry Grant chart for a ballpark initial.

Anything that lowers 'dynamic' compression or allows more exhaust dilution at idle will need more initial.


Another thing to watch out for is the initial isn't the initial.
Easier to give an example.
Say timing is set at 13* at 1000 rpm.
Then when placed in gear, because its not making much power, rpm drops and unknown to us, the timing drops with rpm.
Now its 11* at 800 rpm. Its not making much power, rpm drops and unkwn to us, timing drops with rpm.
Finally it hits the real initial timing at 9* and 650 rpm, its not making much power, so rpm drops to 500.