Originally Posted by cool rockin daddy
yes, you do. You increase the initial. If you run 18-20 initial you are gonna have to reduce the amount of mechanical either by throwing a larger bushing on (when using a distributor with adjustable mechanical advance) or you're going to have to shorten the slots on the advance mechanism. Of course, limiting the mechanical is the most difficult to do if you don't have a distributor that is adjustable but sometimes you gotta do what you gotta do.
That's not the problem. I've already disassembled the distributor, welded up and ground my advance slots 3 times already. I got the initial and mechanical timing dead on it's nuts. We think the problem is the vacuum advance isn't dropping out soon enough causing it to ping when I lightly tip in the throttle. Custom10 pointed out in an above post that the adjuster plate I made for my vacuum advance is limiting the advance from the wrong side. I made another limiter to mount on the opposite side same as the crane one that I'm going to try tomorow.