I want to build a street motor with a good amount of horsepower, but would like to have decent gas mileage. Ive got camel hump heads from a 70 z28 and would like to use those. I will be using a 700r4 and anywhere from a 3.42 to a 3.73 rear end. got any ideas for a good combination. would like to be reasonably priced and preferably a 350 but im open to suggestions.

flattop motor, 280H cam, 3.73's with the O.D.