I found a solution for the discontinued heater control valves for 85-87 Corvettes! A valve from an 82-84 full-sized Chevy is almost identical. The only difference is, the Chevy valve doesn’t have the long length of tubing, or a place to connect the coolant line that runs from the intake to the Corvette HCV.
The Corvette valve usually leaks from 2 seals in the valve and will drip around the screw. You'll find the main seal behind the screw will be all dried out.
