Choosing a carburator

[chinusta]

I have an 87 C-10 with a 350 in it. It however doesn't have the original quadrajet that came with it. It has a metal plate that serves as an adapter and on top of that it has a 302 2-barrel motorcraft carburator. it was originally added because it would save gas. But I'm getting like 8 or 9 mpg. It also has a 4speed manual transmission. I floored it a couple of times and it sounds like dry explosions and I get no power what so ever. Im hoping its because of the carburator. I would like to get another one, but not sure which way to go. some say quadrajet, other holly and others edelbrock. I'm in college and not looking for anything too expensive. I would buy used and rebuilt if possible too.

What I would like to do is get a 4 barrel carb in it and get an automatic transmission as well. I know I have to change the differential, but what is it that I need? Its only a 4x2. I read a little and supposedly I should be good getting a 700r transmission. as far as the differential, I dont know what model to get. and do I need any sensors?... I know I could ask my mechanic, but I dont want to purchase anything I dont need.