hard to do on a comp,,but with what you give for info go thru some steps #1 check dist points then adv,,2 you know the plugs and wires are good???? 3 sounds to me that the problem is in the power system in the carb as going up a hill when engine needs fuel it is getting leaned out and there is your backfiring,,,you should have somewhat the same problem when you go to full throttle anytime if it is in the power system....doc
