[Steve Toner]

Trevor,

Perhaps the issue is not the carburetors themselves, but running without vacuum advance. In that case, you don'r get the advantage of the timing advance at high-vacuum conditions, so must dial in more initial advance. For instance, what I am fighting right now is a slight stumble at tip-in from light throttle cruising (a high-vacuum condition). The suggestion was that I needed more timing, and focused mostly on how to give maximum initial advance. And yeah, if you know how much total advance you have, you're going to have to reduce the maximum mechanical advance when advancing the initial timing - that's what all the bushing talk was about... Finding the best total advance without a dyno will presumably require some experimentation.