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Classic Ford Mustang Ignition - How To: Rebuild a Distributor
MCE Engines and PerTronix show us how to breathe new life into vintage Autolite/ Motorcraft distributors.
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.
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.
Because we have to deal with both hydraulic and mechanical roller camshafts in today's world, we have to think differently about distributor gears. Flat-tappet cams, like those used in vintage 289s, do fine with cast-iron distributor gears because the cams are also made of cast iron. This means neither metal is harder than the other. However, roller camshafts, such as those found in late-model 5.0 engines, are made from hardened steel, mandating the use of either a bronze or steel distributor gear. A cast-iron gear with a steel camshaft will not live long.
Bronze gears have a limited life span and are typically used in race engines. Steel is the gear of choice when you're operating a roller tappet camshaft on the street. So if you're planning to drop your vintage distributor into a 5.0-style block with the roller cam, be sure to replace the cast-iron gear with a steel version, available from Ford Racing and most cam manufacturers.