* A timing light
* A wrench set
* A screwdriver
1. Disconnect the vacuum advance hose from the distributor.
2. Start the engine and let it reach operating temperature.
3. Connect the timing light to the number one spark plug wire and aim the light at the timing marks on the harmonic balancer.
4. Turn the distributor housing clockwise or counterclockwise until the timing mark aligns with the TDC (Top Dead Center) mark on the harmonic balancer.
5. Use your screwdriver through the slot on the distributor base to rotate the distributor while observing the timing light marks.
6. Tighten the distributor hold-down bolt and reconnect the vacuum advance hose.
The timing degree for a 1981 Chevrolet 350 should be set to 6 degrees before Top Dead Center (BTDC).
