Use a delay flash timing light, set the speed to about 2000 RPM with the idle screw, and dial the ball back to the pointer. With the centrifugal and vacuum advance combined, the total advance will be somewhere in the neighborhood of 40 degrees at cruise RPM. The distributor housing will turn a noticeable amount when the vacuum from the carburetor comes up as speed increases.
Jerry
So I'm going to have to pull the distributor to replace the vacuum advance anyway. When I go to timing it again, what is your best recommendations? This is a 1954 3600 chevy with a 235. I overhauled this thing 12 years ago. All I did then was set the octane selector to 0, adjusted the distributor until the BB and pointer lined up, tightened the distributor clamp down and called it good. It seemed to run really well like that, but I'm always up for better advice for tuning it.
