OK I have a stock Ford 302 that I built from a PAW long block kit. Edelbrock 600cfm carb, Performer manifold and a PAW cam (very mild grind idle to 5000) I hear pinging under acceleration. If I remove the vacum advance it goes away. Timing has been set at 12*BDC, 9*BDC and 6*BDC less noticeable with less base advance. I don't know the year of the engine but it uses all standard hardware. At 2800 RPM I measured 42* of total advance with vacum attached. The advance is connected to the timed port of the carb. Is it possible to decrease the amount of advance put in by the distributor while under vacum? I think that if I could do that it would solve the problem. Driving without vacum advance makes the botom end real sluggish in my Scout. I might consider a mechanical advance distributor but I think it might hurt my off road performance. Thank You. Christopher.