Where would you find an underhood wiring and a vacuum diagram for an 81 301 turbo Trans Am?

You can find an underhood wiring and vacuum diagram for an 1981 301 Turbo Trans Am in the vehicle's service manual, which is often available through automotive bookstores or online retailers. Additionally, you might check resources like the Pontiac forums, enthusiast websites, or even specific Facebook groups dedicated to classic Trans Ams, where members often share valuable information and documentation. Online databases or automotive repair websites may also provide downloadable diagrams.