I say to out with gas mileage. I get 8-10 miles with a 1979 blazer with a 350 and stock engine and carb. So if I can increase performance I dont think the gas mileage can get any worse. I also have straight pipe with hedders and glasspacks (cherry bombs). I am not too pleased with the performance of the rodchester carb. So I was looking to put a edelbrock manifold and carb on this engine. I started looking and did not realize there are so many choices. I have choice overload!! I want to keep the price low (Im not building a hot rod or show truck) and I dont want to hurt tork. Any suggestions?! Also in regard to the mufflers I read that straight pipe with glasspipes actually hurt your performance because of no back pressure. I was thinking about buying two flowmaster 40's to put on here. Is that a wise use of $100 or should I leave it alone. Im one a budget. I just bought a set of rancho rsx shocks to replace the stock rusted out ones. Im hoping that will improve my ride....but It hit my truck budget pretty hard. Thanks for your suggestions!!