Prepare the Engine:

• Ensure the engine is at operating temperature.
• Disconnect the vacuum advance hose from the distributor and plug it.
• Make sure all accessories such as air conditioning are turned off.

Locate Timing Marks:

• Find the timing marks on your engine. There are typically timing marks on the harmonic balancer and a timing scale on the timing chain cover.

Initial Timing Setting:

• The timing requirements are going to change depending on your cylinder heads, camshaft, compression ratio, and the curve in the distributor. But a good base would be the 12 to 18 degrees before the top dead center (BTDC). The total timing with advance should be about 34 to 36 degrees.

Connect Timing Light:

• Connect the timing light to the battery following the manufacturer’s instructions.

Connect Timing Light to No. 1 Spark Plug:

• Connect the timing light pickup to the No. 1 spark plug wire. The No. 1 cylinder on a SBC and BBC is the cylinder on the driver’s side closest to the front of the engine. 

Start the Engine:

• Start the engine and let it idle.

Aim the Timing Light:

• Aim the timing light at the timing marks on the harmonic balancer.

Read the Timing Marks:

• While the engine is running, the timing light will flash, and you’ll see the timing marks on the harmonic balancer. The mark should align with the specified initial timing setting.

Adjust the Timing:

• If the timing is not aligned with the specified setting, loosen the distributor hold-down bolt.
• Rotate the distributor until the correct timing is achieved. Turning the distributor counterclockwise will advance the timing, and turning it clockwise will retard the timing.

Tighten the Distributor Bolt: