The ZR1 prototypes were converted standard Corvettes. As such there are a great many differences unique to these cars that differentiate them from a standard ZR1.

The most obvious external difference has to be the standard "narrow" body used on the prototypes. Production ZR1s featured a wider rear body, consisting of unique body panels from the doors back, made necessary by the use of 11.5 inch wide rear wheels. The prototype also does not feature the "square" rear lights used on production ZR1s.

The prototypes are fitted with the originally intended for production "Phase 1" engine that is substantially different from the production LT5. Note the prototype's intake manifold and valve covers in the photo below.

The prototypes, including that sown below was originally based on a stock 1986 Corvette which, at the time, used the "flat" dash. As a consequence they are probably the only C4s to feature an 8000 RPM rev counter. Actual production ZR1s all used the later "wrap around" dash used on all cars from 1990.