Unfortunately, there’s not much good to say about Ford distributors because they’re just not up to the job of high-RPM use. The Autolite/Motorcraft distributor family consists of distributors with bronze bushings, with some having only one bushing and others having two. Because oil distribution is so poor, bushings and shafts wear out quickly causing side play (wobble) and point bounce at high RPM. (This problem also exists with Duraspark distributors). So unless you’re building a stealthy stocker, avoid using factory distributors.
This Tech Tip is From the Full Book, FORD 351 CLEVELAND ENGINES: HOW TO BUILD FOR MAX PERFORMANCE. For a comprehensive guide on this entire subject you can visit this link:
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Because the 335-series Cleveland engine family uses the same distributor as the 385-series 429/460 engines, there are a lot of aftermarket ignitions to choose from. Choice boils down to street or race or a combination of both. Street engines should be equipped with distributors that have a vacuum advance, which operates on throttled vacuums offering initial spark advance during startup and acceleration. Although vacuum advance helps fuel economy and acceleration, it also works hand in hand with the centrifugal advance any time you open the throttle as RPM increase.
There’s a reason why you see the MSD name out there more than any other in racing—and that’s because so much research and development go into its products. And talk about racetrack time? MSD products are tested in tough, grueling environments where they’re subjected to the worse conditions imaginable.
There are three basic MSD units: billet, billet with a vacuum advance, and programmable E-Curve. At press time, the E-Curve is available only for 289/302/351W engines, but as MSD continues to develop its product line, the E-Curve also should be available for 351C/351M/400/429/460 engines. MSD’s E-Curve electronic programmable distributor enables you to dial in all timing elements based on how your engine will be used without changing weights or springs because it all happens electronically. You can adjust total timing, rev limit, rate of advance, and more with this distributor using a small, fl atblade screwdriver.
Outside of the E-Curve, choosing and tuning an MSD distributor is easy. For the street, you want the MSD #8477 Pro-Billet distributor with a vacuum advance. This is a high-performance street distributor engineered and manufactured for ease of use with an easy to access and adjust mechanical advance and a vacuum advance you can adjust with a simple Allen wrench. Mechanical advance is based on Delco distributors of long ago, which were easy to tune because the advance was right under the rotor. It’s a matter of changing spring tension and and/or bushings. This distributor is C.A.R.B. approved.
Two MSD distributors are designed for racing, #8577 and #8569. The #8569 crank trigger distributor fits low in the block if you’re running a tunnel ram or blower. It must be used with MSD’s ignition control. The #8577 billet distributor is mechanical advance only and designed for high-revving applications. You can tune it with ease using the provided advanced springs and bushings.
Mallory still has the same level of reliability and performance it has long had through Unilite technology. The Mallory Unilite #4756701 dual-advance distributor with mechanical and vacuum advance is primarily for street use.
The Mallory #3756701 is a mechanical advance (only) unit with Unilite for pinpoint accuracy. What makes this a great distributor is reliability and its maintenance- free disposition. Aside from the occasional cap and rotor replacement or cleaning the optics, it requires no attention. This is the distributor you want for high-RPM use.
The Mallory #8556701C HEI distributor is a coil-in-cap unit that is all self-contained. Fit may be tricky with the Mallory HEI depending on your Cleveland’s induction system. This distributor can be converted for racing with an advance lockout. And if you choose to tune your Mallory HEI, both mechanical and vacuum advances are programmable and easy to access.
Performance Distributors (in Memphis, Tennessee) enjoys a great reputation for building affordable high-quality ignition systems for Ford applications. Founded by the late Kelly Davis, Performance Distributors is still a family owned and operated business. When you get on the phone with these folks, it’s like chatting with an old friend. There’s nothing you can’t ask them.
Performance Distributors offers two basic types of electronic ignition systems for Clevelands. Both give you factorystyle reliability and easy-to-get parts. For a stock appearance in your Cleveland project, Performance Distributors offers its time-proven #32720 Duraspark ignition. This is a custom-calibrated piece curved for your application. That’s why Performance Distributors wants to know all about your engine when it takes your order. Performance Distributors blueprints every distributor with a full-length bronze bushing, new hard parts, and precision calibration for a seamless advance as RPM increase. Each Duraspark distributor is capable of 10,000 rpm, though I suggest not going there. Please specify flat-tappet or roller camshaft with your order.
Your other choice is the revolutionary #32820 Davis Unified Igniton (D.U.I.), which is based on GM’s HEI system with a self-contained ignition coil in cap. If you want a clean appearance without clutter, the D.U.I. system is your best choice.
The racing D.U.I. system (#328211 with vacuum advance and #328212 without vacuum advance) can handle up to 9,000 rpm. Because it delivers a greater dwell angle, it delivers a hotter spark enabling you to widen spark plug gaps to .050 to .055 inch. Because these distributors are already curved to your custom application, all you have to do is install and go.
When you think of Crane, you think of cams and valvetrain systems; you don’t think of ignition systems. Yet a closer look at the company’s offerings reveals Pro-Curve Billet distributors for 351C, 351M, and 400-ci engines. These maintenance-free, easy-to-curve distributors make light work out of a distributor installation. Made of 6061-T6 billet aluminum, Crane Pro-Curves can be tuned without removing the distributor cap. There are 27 advance curves you can play with to get the optimum power band you’re looking for. Crane Pro-Curve distributors are optically triggered with a magnetic pulse output.
Written by George Reid and Republished with Permission of CarTech Inc