motoTrooper
True Classic
Supercharger wastegate? I know it's addressing the symptom rather than the cause but I just googled up this after reading your post...
http://www.superchevy.com/how-to/engines-drivetrain/sucp-1211-supercharger-wastegate/
http://www.superchevy.com/how-to/engines-drivetrain/sucp-1211-supercharger-wastegate/