There are minor differences in all of the year models. Some are harder to overcome than others, tho. The biggest hurdle is the bumper mount systems, which changes the frame ends considerably. The rubber bumper frames from '75 up are prolly the most consistent, but there are still some minor changes in those too.
If you happen across a frame for a '75-'77, that would be the best, as far as easy swap-out. Other year models will most likely require some modifications, but not too much.
Larry @ Corvette Specialties(or other members) can prolly give ya more specific info on year-year changes.
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Joel Adams
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