Hi
Fordy,
I assume you have the Z22SE engine.
The genuine GM part # is: 24409332 or 24454112 - Gasket, Front Exhaust Pipe to Manifold.
(Not sure why two part numbers are listed, may be worth checking with your local Vx parts dept)
Aftermarket alternatives are:
FA1 - part # 120-918
Walker - part # 80354
Hope that helps.