Finally, it all works Turns out I screwed up somehow when rebuilding the 4100 carb. I stuck my buddies spare holley on it and fired right up. Checked the ignition timing, it was of by 10*. Adjusted that and no more back fire and she runs like a dream. Well, more like a raped ape compared to before I want to say thank you to everyone that replied to my posts and helped me figure this thing out, I can't thank you enough, you guys are awesome