Nothing wrong with the 440. I'm just tired of getting 6 mpg. I should be able to at least double that with the 5.2. I haven't bought the transmission yet, but I have everything else I need. I can't seem to locate an A518 where I live, so I figured a 727 would have to do for now. The truck is a 77 D100, short /wide box, 3.23 gears and 28 inch tires. The 440 runs good, stock 77 engine, RV cam of some sort, was in it when I bought it, 750 Holley, headers and dual exhaust. I can't get by a gas station with it. It was okay when gas was cheap, but not anymore.