- Initial timing: 6° BTDC (Before Top Dead Center)
- Total timing: 36° BTDC at 3000 RPM
The point gap should be set to 0.016-0.018 inches (0.41-0.46 mm).
When setting the ignition timing, ensure the engine is at operating temperature and the vacuum advance is disconnected. Follow these steps to set the ignition timing:
1. Connect a timing light to the engine.
2. Start the engine and let it reach operating temperature.
3. Disconnect the vacuum hose from the distributor.
4. Aim the timing light at the timing marks on the front of the engine. The marks are usually on the timing chain cover or the harmonic balancer.
5. Turn the distributor clockwise or counterclockwise until the timing mark aligns with the "0" mark on the timing scale when the engine is idling at 850RPM.
6. Tighten the distributor hold-down bolt and reconnect the vacuum hose.
Once the ignition timing is set, you should check the dwell angle. The dwell angle is measured in degrees and is the amount of time that the points are closed during one revolution of the distributor shaft. The dwell angle should be between 28° and 32° for a 1968 289ci V8 Mustang coupe.
To check the dwell angle, you will need a dwell meter. Follow these steps to check the dwell angle:
1. Connect a dwell meter to the points.
2. Start the engine and let it reach operating temperature.
3. Read the dwell angle on the meter.
If the dwell angle is not within the specified range, you will need to adjust the point gap.
Always refer to the vehicle owner's manual or a reputable automotive repair manual for specific instructions and specifications for your particular vehicle model and year.
