What Spark Plugs Are You Guys Running On Your Blown 540's And What Timing??

kind of a loaded question..what blower...cooler ? fuel system ?

Stock Efi, 4-5 Lbs, M1 Procharger

hope you have a good retune on the ECM....ac 42 on the plugs, I would get the timing at full advance 26-28..but there is a lot of variables there...from what Ive seen the stock EFI may be a big issure with what you have....I'm running a M3 ona 509, just took off the EFI went to a carb...to much B/S with trying to get the ECM tunied right...some get it right...some don't...if you don't very bad things happen..

What Heads?

You say stock efi, what engine was it stock on? What was HP of engine?