Ummm, bigJ, 220 is pretty good (IMO). Other than that, I would say a conversion to fuel injection would prolly improve MPG. However, that's not a cheap upgrade. Have you tried testing differant grades of gas. How about octane boosters? Try differant things. Oh yea, one more thing. Drive slower and don't haul *** off of the line (from a stop light or something similar). Not saying you do, but so many love to stomp on it and get up to 30mph really quick.
Go fig. I know I've managed to get 50 extra miles out of a tank just in changing driving style.