i recently tried another forum, but i felt that i was not exactly welcome. i hope this goes better. anyway... i have an; ‘86 GMC Sierra Classic 1500 4x4 swb. i has been “Frankensteined”. it currently has a 1980 Canadian 350” out of a california 1 ton van. it has a 700r4 trans. It has a 17066559 Rochester Q-jet (M4MC i think). someone from the other forum said that i have the “dreaded hacked commercial rebuilt) carb. & it’s not rebuildable. can someone Knowledgeable please confirm or deny this? ...& explain why? is this why i’m having so much trouble identifying my carb? is there better Q-jet than others?