Keep the slant and get a overdrive tranny. I have a friend with a 42 Plymouth coupe. It has a 225/ and a 833 o/d tranny. He gets 26-27 mpg highway and has a 4:10 gear in the rear. I'll bet if he had a 3:23 he'd get low 30's tmm
...but easy & 'elegant'. Also, I have to mention this: I had a 4.56 in my well-done 273 & it got about 35% BETTER mpg than the disgusting 2.76 I swapped (I do more hwy). Maybe that 2.76 is just plain wrong for a built V8 small bock, but I figured I'd get a little better. Instead, it went just the opposite...PLUS, no low-end. What can I say, it was free....