[D13]

Originally Posted by Longhorn Man

the biscane MPG has nothing to do with a truck MPG, and isn't worth compairing. Yes, same engine and gearing and weight, but the main thing in MPG is aerodynamics.

2000 RPM with an old school flat tappet cam, carb'd, cast iron, non electronic controlled inline or small block, is 9 times out of ten, going to be too low an engine speed with the barn door aerodynamics of a pick up.

I learned to drive on a 69 C10 with 250/3OTT/3.43 that got 17mpg up until the day the cow went thru the bed floor. We drove the 67 Biscayne to 400,000 miles without pulling the head. We drove it's 66 PG equipped brother to 300,000 until the wiring shorted out and the frame cracked, and got only 19mpg (slipping auto trans). I made the 81 3/4ton get 17mpg just to prove it could be done, and belive me, that's about the most anti-aero brick available.

Aero is an exponential effect and very important, from 35mph up. By keeping speed reasonable and driving carefully you can easily make these trucks get 15-17mpg without an OD trans. Want to run 75 on the highway? Aero says you'll need a lot more HP and thus fuel.

Back to the OP, change your gears to get in the 3.2-3.4 overall ratio (trans or rear swap), slow down, and drive like your grand parents.