I'm with Kurt on this one. You already have a square taper BB. If the spindle races are OK why mess with it? Find a GJC form the early 80's and be done with. In all honesty, by the time your done you'll have much more $$$ into it than it'll be worth.

As the infamous BG once said, "why, dont you buy a a brand new one from bikesdirect for $299 and save yourself the hassle." Or something like that.