As for fuel economy not sure there would be any improvement, you would probably have to rev it out just to get any kind of movement. Like that commodore that came out with the 4 cylinder motor for fuel economy, it ended up as bad as the 6 because the engine it wouldn't move the car without giving it some. Bert have you tuned one up before? Im sure theres a lot of interest as to what can be done and the kinda revs we are talking.