I did a check of Edmunds on a 1990 black ZR-1 in the best condition they list with 6,000 miles on it. The highest price (dealer) was $15,000. Kelley Blue Book had $20,000. However, the NADA has a high retail of $31,500.
A 1995 with the same mileage is $45,000 high on NADA, $34,000 on...