Quote:
Originally Posted by Dragncar
Why would you argue with "that" guy about distributors ?
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Because the big difference between a points distributor, and an HEI, is the point distributor has a centrifugal advance limiter bushing in it, and the HEI does NOT. What limits centrifugal advance in an HEI is the very heavy advance springs- the springs serve 2 purposes, control the RATE of advance, but also the LIMIT of the advance. On a points distributor, the springs only control the RATE of the advance. The points unit will advance until it hits the bushing stop, so the centrifugal advance timing added at high rpm will always be the same no matter what spring is used, it'll just hit the stop at a different rpm. The factory HEI with OEM strong springs are so strong, the centrifugal advance will never reach full advance point within the rpm limits of the engine. If you use the weakest or mid-level springs in a kit, it advances TOO FAR, there is no stop bushing. If you use the factory springs, it doesn't advance far enough. So you have to use a slightly lighter spring than stock, and bump the base timing up to 20 degrees to compensate, and get 36 degrees total timing in within the rpm limits of the engine. Once you realize what you're up against there, it's an easy fix. Drop the strongest kit springs in, with the kit weights, bump the base timing up to 20 degrees, leave the vacuum advance off, and forget it. You have 36 degrees total and the car is a rocket. It's actually easy as hell. I've been working on Pontiacs 45 years now- the best tweaks are usually the simplest, the hard part is understanding the problem first.