Distributors for classic Mustangs are getting harder to find. Here's how to spot the right one for your Mustang.
A couple of months ago, while replacing a worn-out 289 with a Smeding Performance 347 stroker small-block for the Nov. '05 article "Replace a 289 with a 347," we found ourselves in need of a replacement distributor. No problem, we thought as we headed down to the local AutoZone. But there was a problem, as we discovered when the counterman whipped out a rebuilt distributor from an '80s 5.0L.
At first glance, these later-model distributors look similar to vintage small-block distributors, and in fact, they will drop in and work with an older 289 or 302. But on closer inspection, we noted that the newer distributors have several differences, most notably the square opening for the wiring grommet. Granted, you can make it work with the round grommet used for vintage Mustangs, but we preferred a round opening for the proper harness/grommet fit--as well as the resulting neater appearance--with our PerTronix Ignitor kit. In addition, a vintage distributor would assist with our goal of a factory-engine appearance.
A quick call to Mike Ulrey was all it took to locate a rebuilt '66 distributor, but the process started us thinking, how do you recognize vintage Mustang distributors? Fortunately, Ulrey had the answers.
Basically, there were four different types of distributors from '64 1/2 to '73. In '641/2, the distributors were marked FoMoCo and are easily recognized by the capped oil hole for lubricating the distributor shaft. In '65 through most of '67, Mustang distributors were also FoMoCo, followed by a switch to Autolite later in the '67 model year. The Autolite distributors were used through the '71 model year until they were replaced by Motorcraft versions, which were used in '72-'73 and for a number of years after as service replacements.
Of course, from '641/2-'66, all V-8 Mustangs were small-blocks. But in '67, the big-block was added to the Mustang's engine lineup, resulting in the need to recognize small-block and big-block versions. Thankfully, they are easy to differentiate. Small-block and 429 distributors have two cast rings, as Ulrey calls them, on the shaft portion of the body, while FE big-blocks have three. Also, note that 289/302s (including Boss 302) and FE big-blocks have a small shaft, while 351 Windsors, 351 Clevelands, and 429s have a larger shaft.
All vintage Mustang distributors used a cast gear on the end of the shaft. When using a vintage distributor in a 5.0 or other late-model engine with a billet-steel camshaft, the cast gear must be replaced with a billet steel gear.
Ulrey also notes that all Mustang V-8 distributors used a long bushing for the top of the shaft. From '641/2 to '68, the distributors also utilized a smaller lower bushing, which was discontinued in '69, most likely for cost reasons. This led to early failure for many distributors. All distributors rebuilt by Ulrey come with the lower bushing for added stability and durability.
The vast majority of Mustang distributors were of the single-point variety. Dual-point versions were used with performance engines like the 289 Hi-Po, Boss 302 and 429, 428 CJ four-speed, 429 CJ, and some four-barrel 351 Clevelands, including the Boss and HO. As you might expect, those distributors are rare and very valuable today as a result.