unibody repair on a 74 javelin?

[nelsonstrange]

I just bought a 1974 plum Javeline the body shows no external rust.
Althought there are bubbles in a few places under the paint.
I am going to put it on a lift this week. I would like to know exactly what to look for in determining whether or not the unibody it beyond repair.
The guy I bought it from said it is sound and only the floor boards have been fiber glassed. From clawing under it it looks pretty rusted.

[donsjave]

A couple of things here--- Is it the floor pans that are bad? If so, there are patch panels available to make the necessary repairs. They are sold by American Performance and a few others. If the sub-frames are rusted though, it may be wiser to ditch the car. There is also a welded seam that attaches the firewall to the upper floor pan. The question you have to ask yourself is is the car worth the price that you would spend to fix it properly. If not, then it would be reasonable to get rid of the car. Sounds like a nice car, I've always like the Plum color