Well I reset the timing to 12° and used the two medium springs, then added 10° of vac advance. ....wow! bottom end is more responsive and I can lay more rubber:-) engine seems to run cooler. In the past ive tried the aftermarket kits with no luck compared to just adding two medium springs to stock weights, so this time I had to see what all the hype was about with these weights and center plate. Glad I found some. for those who can't find them I had great luck with just the stock centet plate and weights + medium springs from the moroso advance kit on my esc dizzy