It's funny (or not) when you buy a used corvette, how many issues come with it. That relates to just about all generations. Carfax does not cover lots of older vetts. I sold a bunch of chevy parts 7 years ago to a friend when I moved, and called him last month looking for carburators. Sold him the engine 5.7 out of my 77 corvette I received in 2000, engine number matched a 76 corvette production. The car only had 75K miles on it, I was thinking it was a carry over engine from 76 to 77, car had a serial number in the 4400, (early 77) I was told when I bought it it had some rocker valve work done to it, and it ran good wasn't leaking much oil exhaust pipes looked clean. I drove it at times in 12 years, then I moved and pulled the engine, which started to miss. So the guy who bought the engine and I thought it had 85K miles on it. After he tore the engine down he told me it had a hole in one of the pistons, the cylinder heads didn't match and had .040 pistons in it. I think that is not original,I was surprised, no such thing as checking too many numbers.

 

I can tell you a story with the same issue about a '75 Chevy truck my dad bought from the dealership in '77. Had 20,000 miles and a cobbled up junkyard engine.....
a lot of these cars were rode hard and broke when new....