[Mustard72]

I had a 4.57:1 Eaton rear end in mine before I tore it all apart. 3200 RPM at 60 mph with stock sized tires (29" diameter or so). Lots of low end grunt with that rear end for a stock 350. That being said, I've had the truck since I was 16, and it's seen the high side of 100 mph more than once. That comes in at about 5300 RPM, but it didn't seem to have too much trouble getting to that speed. Don't get me wrong, it was no drag race star or anything, but I'm thinking your truck should easily do more than 65. Something's wrong. Lots of power, no acceleration, and 65 top end don't add up.

I also don't think a C20 with a V8 would have come with a powerglide in 72. More than likely a TH350 or TH400. The TH350 has basically a squarish pan with one of the corners angled. The TH400 has a more irregularly shaped pan.

I could get 10-12 mpg with mine typically. Once I got about 14 on a fresh tune up, but that was pretty much a rare occasion, and subject to debate (like most mileage figures).