Dash instruments does not work on 1992 Chevrolet Corvette

installed new key ignition, computer rebuilt, now dash instruments does not work

The early Corvettes dash is controlled by the BCM or Body Control Module. Which Computer was rebuilt because I have had very poor results from 'rebuilt' ECMs and BCMS in Corvettes, even from the factory.

this could be a problem because the key signals many things on your car, not just the ECM, the BCM is involved too.
The ECM was rebuilt to use a regular key instead of the chipped key.