[namba209]

To amplify the thread by madhatterpc, in a couple of things he stated, I increased my MPG and performance in my 71 Dodge van by changing engines. The cam gear broke on the original 318 cu. in. and trashed the engine big time. I found a NASCAR built 340 cu. in., and dropped it in. My mileage went from 17 MPG on the 318 to 21 MPG with the 340. The reason was simple. In order to move 3 tons of van I had to use a higher throttle setting with the original engine and a lower setting with the 340 with a lot more horses available. Performance between the two engines was definately noticeable. Prior to changing the engines, I had already installed a 426 Hemi auto tranny, and the van came with a 4.10 Trac-Lok rear-end. I do believe, by seat of the pants technology, the van is much quicker than my monza, up to a point, then the frontal area of the van comes in to play somewhere above 45 MPH. The point here being more horses can do the same or more work with less fuel consumption.