The Stovebolt Site Forums The Shop Area Engine Shop Help -- 305 V-6 backfires through carburetor

A flat cam that will not let the exhast valve open will cause it to back fire when the intake opens because it doesnt clear out the exhast pressure also a burnt intake valve will back fire through the carb because it doesnt seal,but I would check compression ,recheck your condensor and points real close, mabey try a new set if the compression is good ,I have gotten bad parts new before , also put a vacum guage on it if a valve is not sealing it will jump up and down rapidly .also a spark will miss fire when its under a load Good luck