A 305 or 350 would have plenty of power to propell it. As far as performance parts and feul mileage, it depends on what the part is and how it's designed to work. Some things, like cams, can be designed to do both increase power and help mileage. The newer oiled type air filters is another one that helps, along with the better flowing exhaust systems. There are EFI systems on the aftermarket that can off decent mileage, too. If you want to gen 111, either make sure to get the computer and harness from the doner, or use one of the aftermarket control systems. I beleive that they would offer as good or better mileage than an older carbureted system.
