Carb backfire

[Cutty454]

Im having problems with mt carb backfiring about three weeks ago it was backfiring out the carb so me buddy adjusted the timing and the carb and i took it for a ride and it was fine ran great so i parked it well i came back a week later and its doing it again so my buddy adjusted the timing again and its still doing it i went out and bought a new distributer and still doing it the car does have bad gas in it and when we puled the plugs they were black sooty and the wires are cheap so im gonna try changeing plugs,wires, and fresh gas and see what that does i was just wondering what you guys thought. I thought it might be the carb but i dk and i dont wanna go buying another new carb or rebuilding this one if i dont have to

 

[megaladon6]

what carb do you have? if it's the CCC system with an O2 sensor ther is a limited amount of adjustment and the O2 sensor may be shot.

 

[Cutty454]

It's a holley I can't remember if I bought a 700 or a 750 manual choke double pumped