I agree with VonTingler, too. Why have an old truck if you rob it of its personality? Stick with the solid axle and put a set of mid-'70s GM disc brakes on it. Also, if you don't like the physical workout of steering it, you can reproduce the stock '50s GM linkage-type power steering with a C-3 Corvette PS system and a little re-engineering of the drag link. I did it and my '59 Apache steers easy and smooth.
Good luck.

Apache Kid
1959 Chevy Apache w/\'79 Corvette engine