I think the 1990 ZR-1 is not at a high resale valve. I bought it new with a dealer order in mid 1989 got it 1-20-90 and paid list (59,995.00). at the time it was like buying a CVO.
most dealers wanted from 12,000 to 25,000 over list, so their are some out their that some one paid 90,000 to 100,000 for it.
It has been falling in valve for the last 15 years and is at a low point now. Still might go lower, no one knows.
the 60,000 to 100,000 mile ones are 15,000 to 20,000 now and over 100,000 + miles are the 15,000 and down to a low of 7500.
the motors were built to the hilt, no problems with 100,000 + miles.
their are some small things that will need to be replaced, like the starter if it goes bad and you do need to pull the top off to get to it.
don't want the starter problem.......never wash a ZR-1 motor! worst thing you can do to it.
if you do have a problem that you can not fix, their are three shops one in Chicago, TX, and KY, that can do major motor rebuild, and the parts can be found.
Dean Nelson