I'm gonna put a 4bt/3.9l cummins diesel in my Dodge. just lookig for the right bread truck to pull it from. These are a turbo 4 cylinder.
There you go, I bet you'll get 30mpg.
Just think, if you do some research I bet you could even run that engine on used deep fry oil/bio diesel and have the best smelling van in the neighborhood.
I was thinking of using a 4 banger out of one those little D-something mini pickup's that were around in the early 80s. It was a rear drive truck so I'm hoping it would bolt up to an over drive automatic transmission from a newer car.
I would sacrifice high performance for good gas mileage, don't need a Van that runs 0 to 60 in 6 seconds, if it gets there in 10 to 12 seconds, that will be fine with me. I live in FL so I don't need mountain climbing power, a Van going down the road 55-65mph only needs around 60 horsepower max. 75 if the A/C is on.