Then maybe sway bars front and rear.
mustang II suspensions. Is that a recommended upgrade?
No. Way undersized for truck use. Plus, to make it work, the geometry of the suspension is reversed from the way it was intended to work. There's also issue with some of the big name companies (who should know better) using parts for purposes they were never intended for, causing potentialy dangerous failures.
While I'm no fan of using a clip, it would be the better way to go. You could also use a weld in crossmember that uses GM intermediate/F body suspension, which is much better than Mustang 2/Pinto components. There's also a few guys on here that have adapted the front susepnsion crossmember from the '73-'87 Chevy trucks to fit, keeping a tru pickup suspension with the IFs ride and disk brakes.
That said, the stock axle and suspension, properly rebuilt and upgraded (gas shocks, sway bar, radial tires) will ride and handle much better than one might think. Disk brake conversion are available for the stock 1/2 ton axle in boht 5 and 6 lug patterns, though the 6 lug version will not work with stock wheels.
