Been so long since I've had a car w/o a computer and could adjust the carb that I have forgotten what back firing through the carb represents.....too much air, or not enough. Please refresh my old memory.

Oh yeah, you might want to know it's a 230 cu in, 6 banger with a one barrel carb.

Backfiring through the carb is ignition in the cylinder when the intake valve is open. Try and adjust the timing.
Chris