So, I change carbs and see what's up. The Edelbrock does run rich I stepped it up just because I got some more umph out of it. The exhaust is Flowtech headers, 3" to 2and a half collectors, a T crossover pipe and knockoff Flowmaster mufflers. It amost seems to pop in the right muffler too. These pops intake and exhaust always show up at the same time. Other times the engine runs great. I did check header bolts and collector bolts but didn't find anything obvious.

Ok, so i'll put the super glut Holley back on and see what's up. I'll bet at this point you're right.