a buddy of mine just bought a 85 custom deluxe chevy...the original engine was a 4.3 TBI but the last owner\ had a 350 put in and a turbo 350 trans. anyways its been running like crap so we went ahead and changed the plugs (took 5 min in that thing) they were gapped at .040 so we gapped the new ones at that. all we know is its a 350, q-jet carb, edelbrock RPM intake, feels like it has somekind of cam in it, other than that i think its just a stock motor out of a truck or something. what should the gap be? we get it right? right now it jumps around at idle pretty bad and likes to backfire under accleration...weve never messed with carbs before but i buddy of mine says its probably running lean because its trying to die at idle....sometimes does die but with gas it stays running...since he has no nuetral safty switch he just sticks it in reverse and then starts it so it doesnt die...so far it works fine cept once he accidently hit his house (lol didnt hurt either) because he started it in D and didnt know it. also could it be out of time? its really slow i know its a huge truck but it seems like a decently built 350 should power it pretty good