Probably an aluminum block this time.
a Tomahawk block? nice. raised cam / deck or you plan to stick with the stock timing cover and intake?
or some other update that can't be seen to help with the mileage issue.
200r4 swap would get you OD as well as a shorter first gear.
or you could pull one of these new 6 speed automatics out of a 1 ton pickup. that would get you at least 2 OD gears and a lockup convertor in a trans that can hold 800 lb-ft all day long. you'll be running 70mph @ 1200 rpm.
The way to crush the bourgeoisie is to grind them between the millstones of taxation and inflation.
Government schooling is about "the perfect organization of the hive."
H.H. Goddard, Human Efficiency (1920)