Thanks for the speedy reply.

I'm running a Holley 80457s carb (Shiny 4160, new). I switched out the shooter from a .31 to a .35 (works better) and am running a red cam on the carb. Once it gets on the main jets it is *very* strong but I am still having a persistent backfire through the carb during transition from the idle circuit to the mains. Its almost as if it is leaning out just after the transition circuit and just before the mains.

Disturbingly, I just noticed that the passenger side of my 8011 dual plane intake has a very small residue of oil in it (could be unburnt fuel? but is too slippery for that). How on earth could I get oil in the intake? Mind you, its just a little bit but enough to bother me as I know of no way to get oil in the intake short of a busted piston or rings (this is a new engine!).

Thanks,
Tracy