I have been having problems with my distributor and getting the advance curve to work right. I started off with the centrifugal advance sticking and no vacume advance at all. I fixed both those problems, but the engine still likes to pop on me in th upper RPMs (3000 or higher) at high throttle. Everything in the distributor is OEM or OEM replacement parts. Here is the current numbers... 1. initial timeing is set at 10 degrees. 2. centrifugal advance gets the timeing up to 25 degrees by about 2500 RPM but no higher. 3. total advance with the vacume advance pluged in is 40 degrees. I am guessing that my problem is with the centrifugal advance. Shouldnt it add about 20 or 25 degrees making a total advance of about 30 degrees with the vacume advance unplugged and about 50 degrees with the vacume advance plugged in? Thanks for any help?