No need to swap frames, in my opinion. You can put in an IFS via a Mustang II kit and a modern rear, including disc power brakes and rack and pinion. No advantage over an S-10 chassis that is obvious to me.
Look at this:
http://www.zigsstreetrods.com/Pages/trucks.html#MustangIIIFS just the first hit I googled, no affiliation, just an example.
If I was going to a pretty torquey motor, I might box my TF frame, but they came with 283 small blocks stock.
