No wonder my 428 pings then because my vac advance is hooked up to the carb and draws a constant vacumn when the line is hooked up.I set it at 9 degrees and it pings so bad when it gets warmed up I retarded it to 4 degrees and it still pings some. I bought it this way so I guess I need to get the ported vac system for it to ever work right.This helps me with my 350HO Firebird too when I get it in and cranked.Does the timing stay the same no matter what cam you use??
