New to the A body scene, school me!

If want it to handle well then do the suspension a chassis work first. You will be suprised how fun it is to drive an old car that can corner, even with a little 273. If I was in your position I would get the car handling the way you want it to. Drive it while I build a nice 400 hp 360. Throw a four speed in there with a 8 3/4 or 9 inch then be done with it. Maybe go with a 8 1/4 rear just because you can get rear disc for those easy.