Classic Ford Mustang Ignition - How To: Rebuild a Distributor

A lot of energy has gone into making small-block Fords perform better during the past 44 years. Those first small-block Fords-the 221 and the 260 Fairlane V-8s from 1962-were fairly tame with an Autolite 2100 two-barrel carburetor and simple point-triggered ignition. Four-barrel carburetion didn't come until 1963 and only on the 289 High Performance. Each passing model year produced better small-block Fords: the 289-4V of 1964, 302 for 1968, the Boss 302 and 351W for 1969, a close cousin called the 351C for 1970, 400M for 1972, 351M for 1975, hydraulic roller tappet 5.0L (302ci) High Output in 1985, and the fuel-injected 5.0L High Output for 1986. In the late '90s, Ford eliminated the distributor completely in 5.0L Explorers.

Great engines need solid, reliable ignition systems to become legendary. The small-block Ford is no exception and neither are other Ford engines such as the FE-series 390/428 and the 385-series 429. They all need ignitions that will reliably fire the mixture for thousands of miles. But running these old Autolite and Motorcraft point-triggered distributors is like taking a slingshot into a nuclear war. You don't stand a chance because it's a woefully inadequate design, especially when compared to today's technologically advanced ignition systems.

Our subject is a '66 Autolite single-point distributor from a 289-2V Mustang. What we're about to teach you applies to any Autolite or Motorcraft V-8 point-triggered distributor from 1962-1974.

What makes these old Ford ignitions inadequate is poor shaft support, insufficient and limited point-function, and a crummy breaker plate. Sloppy breaker-plate movement, shaft oscillation, and point bounce all keep a tuner guessing about dwell and precise ignition timing. We're going to show you how to keep the old Ford distributor and gain a reliable ignition system at the same time.

Marvin McAfee from MCE Engines will walk us through the blueprinting of an old Ford distributor. He stresses a process that leaves no stone unturned. His message is basic: You can't trust mass-produced remanufactured components from typical discount auto-parts stores, especially for your Mustang's ignition system. Because Marvin is a diehard Ford enthusiast with a deep racing history, you can trust his judgment and expertise.

Even using the best parts from a Motorcraft tune-up kit, old Autolite distributors don't hold up well in regular operation. As point-rubbing blocks wear down, dwell changes and performance suffers from changing point gaps and burned contacts. You would be surprised how many enthusiasts drive Mustangs with inoperative vacuum-advance units. Vacuum advance gets a car started under acceleration by retarding the spark at low rpm and handing off to the distributor's mechanical advance (advancing the spark) as rpm increases. Without vacuum function, engines don't perform well when it's time to accelerate. During cruise conditions, the vacuum advance maximizes fuel economy. This is the original shim-style Ford vacuum advance common in the '60s.

You would be surprised how many enthusiasts drive Mustangs with inoperative vacuum-advance units. Vacuum advance gets a car started under acceleration by retarding the spark at low rpm and handing off to the distributor's mechanical advance (advancing the spark) as rpm increases. Without vacuum function, engines don't perform well when it's time to accelerate. During cruise conditions, the vacuum advance maximizes fuel economy. This is the original shim-style Ford vacuum advance common in the '60s.

Marvin points out things few ever consider. There are many weaknesses in vintage Ford distributors, including a single shaft bushing (later versions have two), a flimsy breaker plate, points that don't always remain in proper alignment, weak grounding, and the primary ignition lead.