Looking for Opinions, Every Opinion Counts! Chevy 305ci

[DOS989]

Whats up guys! I know a little about engines but not enough. I've got a stock 305 from a 1993 Silverado I'm gonna get put in a 1991 Mitsubishi Mighty Max pickup. We are going with carb because the guy doesn't wanna set up the throttle body computer stuff. I'm doing this for two reasons: Fuel economy and Power. Before anyone gets all these ideas why I shouldn't do this, first let me tell you the situation - I bought this truck for a daily driver, its perfect and ideal in every way I can think of as a daily driver truck, exactly what I've been looking for all these years. The problem is, it only gets 1MPG more than a Chevy 454SS. Thats right, only 13MPG. Mechanics around here have looked and say the engine runs excellent, you couldn't ask for a better running engine, but they don't know why the fuel economy is so bad. I don't really know for sure either, but my guess would be that it wasn't set up properly, likely in the computer (its fuel injected, with MAF and TPS and that mess) since it was converted from carb to fuel injected. Whoever done it did a good job, everything looks like its in the factory spot for 93 - 95 models, it just gets awful crappy gas mileage. I've already done months worth of various tests to see if the economy improves, but no luck. Anyway, I'm gonna end up spending more than the truck is worth trying to fix that, so I've decided to take the 305 I've got from the 93 Silverado and get it put in this little Mitsubishi. My installer already said it'd fit, he's a well seasoned mechanic and his brother is a machinist, so I'm confident in the fitment. So here is what I want to know - normally I'm pushing for power as well as fuel economy, but having decided to go with a carb, I figure I'll concentrate on getting the best MPG possible - so then, what kind of carb should I use on this stock 305 (formerly Throttle Body) V8 engine to get the best fuel economy? My installer said the throttle body intake can be made to accept a carb, I don't know how much influence that'd have on what goes on top...
Please let me know! Thanks!