I've had a lot of off & on trouble getting my 52 GMC to not hesitate and to just generally run well. FINALLY FIGURED THE PROBLEM!!! For some reason I never loostened the vacuum advance from the distributer. When I did that I was able to get the timing advanced far enough to make the little 228 RUN. The timing light is useless though because the marks aren't anywhere they are supposed to be. BUT WHO CARES.
My wife can drive it now cause there's no hesitation and lots of low and top end power.
I know I'm probably not the only temporary bonehead out there so I thought you would appreciate the story.
Jim