292's were built for torque, not fuel economy and their usual application was for 3/4 ton to 2 ton trucks where fuel mileage was not much of a consideration. Most of the ones I've worked with get somewhere in the 12-15 MPG range, loaded or empty, depending on rear axle ratio. I've never seen a 292 that can average MPG in the high teens or low 20's, regardless of what kind of vehicle it's in.
Jerry
