Need a solution for a problem.

So supercharge or boost with fuel injection? Or 318/360 magnum swap?
I like the way you think, but the slant can be fun with a 1:1 A833. If I was you I’d either swap in a non od 4 speed, or swap to a 5 speed.

A V8 will make the split more tolerable but that transmission will never be fun, in my opinion,and from my experience running one behind a slant and a small block.