Big Block Conversion, do it again?

I did a couple of 440/A body swaps in 79,and in 82. Enjoyed em both and they were "easy fast". Do it again @ 3.00 bucks a gallon....? Nope, Not untill I figured out away to get 20mpg to drive it daily. Was gonna do one I have now, but 10 mpg don't cut it anymore. Goin LS3.