How to Set the Points on a Ford 390by John Stevens J.D.
From its inception in 1961, Ford's 390 cubic-inch, big-block engine had one set of ignition points underneath the distributor cap. As the spindle in the center of the distributor turns, a cam at the bottom of the spindle opens and closes the points. The distance between the tips of the points at their extreme open position is referred to as the gap. Over time, the gap tends to fall out of adjustment and the vehicle's owner must periodically readjust the 390's points, which generally takes only a few minutes.
Unfasten the two clips that secure the distributor cap to the distributor. Remove the cap by prying the clips away from the cap with a screwdriver.
Lift the rotor arm off of the distributor's spindle. The spindle is the vertical metal rod in the center of the distributor. The rotor is the plastic piece that features a metal tip. The rotor arm is located on top of the spindle.
Loosen the two sheet metal screws that secure the points assembly to the bottom of the interior of the distributor.
Rotate the distributor's spindle until the cam fitting at the bottom of the spindle opens the points. The cam fitting is located at the base of the spindle and resembles a large nut that would otherwise secure a bolt.
Insert a feeler gauge of the proper thickness between the tips of the points. Use a 0.017-inch (0.43 mm) gauge if adjusting the points on the standard 390 or a 0.021-inch (0.53 mm) gauge if adjusting the points on the high-performance 390 from 1969.
Adjust the points to their proper adjustment by moving the bottom of each point's assembly with a screwdriver. The assembly is properly adjusted when the feeler gauge fits snugly between the points.
Tighten the two sheet metal screws that secure the points assembly to the bottom of the distributor.
Press the rotor arm onto the distributor's spindle.
Lower the distributor cap onto the distributor and press the cap's two clips onto the cap to secure it in place.
Items you will need
- Standard screwdriver
- Feeler gauge
- "Motor's Auto Repair Manual"; Ralph Ritchen; 1968
- "Chilton's Repair & Tune-Up Guide: Mustang / Cougar, 1965-73"; Chilton; 1998