The 383 I mentioned had a rocker off an exhaust valve. The fuel was getting in
and combustion was happening... exhaust was coming out the intake valve the
next time it opened and popping through the carb. Purely a mechanical issue. If
I recall correctly you posted that carb popping was "ignition" which would imply
electrical. Which isn't always the case. that is what I was pointing out. Things
aren't always plugs and wires, you have to pull a valve cover and check and see if
a cam lobe is wiped out sometimes. I say this because I listened to the guys
engine saw how much pressure was coming out of the carb when it backfired and
said "that's valvetrain, pop a valve cover off..."
