A few things I have tried that didn't seem to make any differance in MPG.

I got a 72 340 4spd TQ on it and it is about the same, mabey a little more throttle responce but
Lossened up the valves to reduce over lap and increase vaccume. It made it more responsive and smoother idle and vacume went up but not a noticable differance in MPG.

I have tried monkeying around with metering rods jets timing curve ect and nothing seems to make any differance. I drove it accross the country this summer and it seems to like E-85 but not any differance in mpg.

Since the basic build no amount of tuneing and such has made a big differance. Any gains have been pretty small. Driving slower did not seem to make a differance, never have made 30mpg even doing 50 mph across the plains. Over 65 though it does start droping off. I think it is just turning to many RPM.

If the 318 in my 91 dakota would ever blow up I will put this motor in it along with a 5 spd and the tbi some 92 magnum ex manifolds and 3.23 gears.