Here are the steps involved in installing a 1972 Pontiac 455 engine into a 1980 Pontiac Trans Am:
1. Remove the 1980 Trans Am engine.
2. Prepare the engine bay.
3. Install the 1972 455 engine mounts and brackets.
4. Install the 1972 455 engine.
5. Connect the engine to the transmission.
6. Connect the fuel lines, coolant lines, and electrical connections.
7. Install the exhaust system.
8. Perform necessary tune-ups and adjustments.
Please note that this process may require additional parts, tools, and expertise to ensure a successful and reliable engine swap. It is always recommended to consult with experienced mechanics or professionals before attempting such an engine swap.