Hey i have the same thing with my '71 Conv. The footwells for the back seat are completly rotted through, and the unibody is also in rough shape. Mine only has a 302. But when i got that i got two junk cars that dont run, and one is a '73 coupe, that has no rust, needs a new interior and paint job, and the other is a '72 coupe, with a "good" 351C. It doesnt run at the time, it doenst have a radiator, but it has oil in it, so a rebuild kit would have it working great. I didnt get the titles on the two junk cars, i already checked and they are not reported stolen, but i have to track the title down before i can fix that one up. If all goes well i will be selling the conv.