Seriously, if you want something you could drive around town and hit the highway with too, then how about a 3.55 or even a 3.73 rear with a good dual plane intake. Keep the spread bore carb and put a nice set of headers on it with a multi-spark ignition. Maybe a little smaller cam to make use of that 10.5:1 compression. You can blend streetability and performance if you want or go fully one way or the other. That`s a choice you`ll have to make before you do too much one way or the other. I like a car I can drive.