[LKLusza]

Originally Posted by 68ragtop

Larry, What heads are you running? The smaller chambered heads (<72) combined with pistons that are below deck at tdc can be prone to dentation. Has to do with the flame spreading out over the piston in a larger area & creating more heat. zero deck bumps compression but keeps the ignition in the chamber. I have the factory 16 heads, 068 cam, Q-jet & a lowly oe point ignition system with no pre-igntion at all.

I have the #13 heads. They allegedly have the 72cc chambers and big valves. The PO added hardened seats in addition to the usual overhaul items.

I have the same curve I had before w/ the carbs and while they pinged like crazy, the efi does not. So, I think it was a jetting/metering/issues. Either way, the efi works really nice.

FYI: The curve I have in the distributor right now is:
14 deg initial
34 total mechanical / all in by 3000
16 vacuum
This gives 34 total and up to 50max cruise
I just came back from another drive and have no pre-ignition whatsoever.