[justcuz]

I would get it running and put a reliable heater in it. Then drive it for a few thousand miles and see how the body holds up. If the body mounts are shot and the floors are real bad it might not be worth saving.
Look for a G86 on the glove box door. I think that denotes a Detroit locker.
with a little work you can install power steering, and power brakes and even put front discs on the closed knuckle front axle.
I would be inclined to keep that six if it is a 292.
Is the Rockwell married to the SM420? The only draw back to the Rockwell is parts availability. The rear intermediate shaft bearing retainer is aluminum as I recall and I wore one out. It was tough to find a replacement.