PRI 2011: Mark Williams’ Modular 9-Inch Housings

The Ford 9-Inch

Introduced in 1957 and in production until 1986, Ford’s fabled 9-inch rear end housing is a semi-floating, dropout axle whose design has been utilized and tweaked by the performance aftermarket for decades and is largely considered the superior design for performance and racing vehicles.

Generally, when selecting and purchasing a rear end housing more a street-type application, what you’ve got is what you’ve got. The axle tubes and four link brackets are affixed to the assembly, and if you decide to change up your measurements for narrower or wider wheels/tires, you’re looking at either a new housing or some modifications in a fab shop. Fortunately, in racing applications these days, there’s a better way.

Colorado-based Mark Williams Enterprises offers a full assortment of housings and housing components as part of their MW Modular lineup and brought one of their 9-inch housings to the PRI Show to display to attendees, which we simply couldn’t pass up the chance to take a closer look at.

In browsing the Mark Williams catalog, you’ll find a number of variations of 9-inch Modulars, including Steel Tube, Pro 4-Link, Full Floater, and Econo/Comp. The centers for these housings are made from a high strength alloy that, according to MW’s Bret Goethe, are 30% stronger than billet. To compliment the centers, Mark Williams provides a complete line of spacers, 4-link plates/brackets, solid mount (dragster) plates, and end bells to create a virtually endless number of overall width and 4-link combinations possible with the very same housing center.

The particular housing on display here at the show sports a 16-inch 4-link setup with two support bars to create more torsional strength under high horsepower, high torque load. Adding to the overall strength of the assembly, the spacers, brackets, and end bells all have pockets in the ends, taking the load off the bolts and placing it on the physical structure of the components.