Mark Williams 

​The Mark Williams 12" Modular is the only rear end in drag racing that offers a warranty on gear sets. That is how confident we are in the strength of our rear end. Every racer wants reliability and consistency, there is no better way to do it than with a modular rear from MW. The modular design makes it easy to dial in your car to your needs. You can change wheel widths, center widths, or even the mounting style. It is even easy to change from a flange axle to a floater. MW modular rears are manufactured from a special high-strength aerospace alloy that has proven to be far more rigid and precise than fabricated steel housings. We can use Ford 9", 9-1/2", and 10" or MW 12" gears, but the strongest -by far- are the MW 12" gears​