So i found rust eating at the door frame, can this be fixed?
Have to ask....If the floor pan and door frame is this bad, what does the frame look like?
May be worth finding a better body to start over with.
I've gone this route with the 79 Monte Carlo in my avatar. Found rot in the roof, structural areas of the "A" pillars, frame and most of the body mounts.
After a 5+ year search I purchased a 13,000 mile replacement which came down the same assembly line 22,000 units later.
Needless to say the avatar car will give up all the goodies added to it for the replacement car.
The cost to repair the black car would have been twice the purchase price of the replacement car.
Not the answer you may want to hear but, having been there it may be a less expensive option.
Best of luck!
Bob S.