Your engine is a 5.3L not a 327. It would be closer to 325 cubic inches. It is most likely a 1/2 ton, or 1500 truck, but if you call your local GMC dealer, and give them your VIN ( vehicle id number) they can tell you just what you have. Ask for the parts department. Your VIN is on your dash, on your vehicles title, and vehicles registration.
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