1966 Valiant...should I part or fix it?

I was just about to suggest you part with the parts and start over. 1K toward another solid project would go along ways toward a sound body and frame combo, the rest can build upon a solid foundation. Buddy of mine just found a 55 Stude truck built on a later Ford frame, disc front end, 400M motor, AOD trans, painless wireing harness and a 9 inch, and NO frame rot for 1500. It aint a Mopar but kinda cool none the less. Looks like it was the inspiration for the chevy SSR, almost the same lines. But your saving it, good luck on the torsion bar seats, if you get the entire crossmember, you should be ok there.