Front spring perch width for GM trucks was unchanged from 55.2 through the last straight axle 4x4 truck in '91, so any gm front axle (10 bolt, dana 44, dana 60, gm napco, etc.) will bolt right up.
If you want front discs, look for a k10 front axle from a squarebody chevy. Those dana 44 or 10 bolt axles are pretty easy to find for $300 or less. It will be a good upgrade for your front axle.
If you do end up changing your steering box, be sure to post it up for sale on the forum if you aren't going to keep it. They aren't too common, and I need one
