It would be a hard pass over 5k for me.
Why?
SBC will go to 200k with just valve seals, why was this one rebuilt?
Garaged 25 years but needs paint?
headliner I can understand, but needed seats recovered?
Crossfire motor!
Sounds like this car was abused.
Comparable-
1988
https://www.ebay.com/itm/1988-Chevro...etpar&LH_BIN=1
1984 Z28 already painted
https://www.ebay.com/itm/1984-Chevro...eqiIe&LH_BIN=1