Backfiring out carb and wont run right

I had problems with a slant 6 with rough idle. It didn't spit fire through the carb but was a fuel delivery problem. Had a fitting sucking air. When I fixed that, it ran fine. You could have more than one problem. Need a friend with a spare carb. Check the fuel line from tank to carb. Could be a counter weight in the distributer sticking.