Mark Williams Enterprises has developed a driveline reliability solution for racers with high horsepower applications —like Top Sportsman and Pro Mod among others— who wish to employ wheels with a 5-on 4-3/4-inch bolt circle. This mounting pattern is compatible with a wide variety of wheel styles, including many bead-lock designs.

Now available from M-W is full-floater modular rear end assembly that uses big 10-inch pitch diameter ring gears for optimum reliability. These gears measure 9.430” in diameter, but use the pitch diameter of a 10-inch gear without the extra weight. They are available in 11 ratios ranging from 3.70 to 6.20.

The modular 9-inch Ford-style housing, originally developed by Mark Williams Enterprises, has been refined over the years and is at the pinnacle of perfection. Advantages over fabricated steel housings include precise alignment of all internal components due to close-tolerance CNC machining, resistance to deflection under high horsepower launches, and flexibility due to its modular construction. The unit can be adapted to other vehicles by essentially changing end bells and brackets. They are available with solid mounts, or for 4-link setups (17-1/4-inch minimum link centers).

M-W’s center housing is cast from a special aerospace aluminum alloy that is 30-percent stronger than other units on the market and features special reinforcing ribs. Moreover, there is zero internal stress —unlike steel housings that have been bent and welded.

Full-floaters are a preferred option to standard flange-type axles due to their added safety factors, and are required in certain classes. The extra-strong axles are forged from 4340 or 300M  alloy,  and feature optional gun drilling up to 1” to reduce weight, and have a 40-spline design with true involute splines.

Each assembly comes with M-W’s highly regarded 10-inch Severe Service third member with it’s Mark Williams-developed through-bolt aluminum case. Main bearing bores have been increased to 4.000-inches and employ special angular contact ball bearings and have a ball bearing pinion support.

Brakes are an issue with smaller diameter 15-inch bead lock wheels, and like all M-W floaters it comes with 11.375-inch diameter rotors that can clear the lock ring on the wheels. Special carbon/carbon brakes are an available option.

Everything is manufactured in-house at M-W’s facility in the Colorado Tech Center in Louisville, CO to the industry’s highest standards. The facility boasts a proprietary torsional testing device that can exert 15,000 lbs. torque in computer-controlled cycles and is used to test and validate components.