Detroit Speed - Archived Differential - 070881-331DS

The Detroit Speed FN988 Torque Arm Differential delivers next-level performance for 3rd and 4th Gen Camaro and Firebird builds, combining the quiet efficiency of the Ford 8.8 gear set with a dropout center section and integrated torque arm mount. Designed for cars running a 9”-style housing, it blends the strength of the Ford 9” with the smoother, more efficient design of the 8.8 - offering a modern, refined solution for high-performance applications. Featuring a 31-spline Truetrac differential, 1350-series yoke, and five available gear ratios, the FN988 is built for uncompromising strength, control, and reliability—engineered, tested, and proven the Detroit Speed way. ENGINEERED FOR STRENGTH Detroit Speed’s FN988 Torque Arm assembly sets the standard for precision and performance in differential design. The integrated torque arm mount eliminates the need for additional brackets common in 9” axle housing swaps, improving the tight packaging constraints in 3rd/4th gen F-Bodies. Each case is cast from high strength nodular iron and machined to exacting tolerances. Forged steel bearing caps further increase strength in high horsepower application. Assembled with a 31 spline True-Trac Differential, Ford Racing gear sets, high quality bearings and heavy-duty 1350 yoke ensures durability under modern power levels, making it ideal for high-horsepower LS and LT builds. TRUSTED BY TOP INDUSTRY PROFESSIONALS Designed with professional builders and advanced enthusiasts in mind, the FN988 is trusted and used by many of the highest quality build shops in the country. The quiet, efficient operation offers a level of refinement consistent with the high quality builds across the countryIts precise geometry, housing alignment, and superior materials make it the perfect foundation for Pro Touring and performance builds requiring exact tolerances and modern driveline control.

Note: OPTIONAL REM POLISHED GEARS Detroit Speed offers REM polished gear sets to further improve the operation of the rear differential assembly. Look for “-R” on the part number for optional REM treatment. What is REM treatment? This polishing process creates a smooth micro-textured surface on the gearset for enhance oil retention properties. Commonly used by racing professionals looking for every advantage, the result of REM treatment is reduced heat and friction, increased component life, and quiet, efficient operation. FITMENT NOTES Fits: 1982–2002 Chevrolet Camaro & Pontiac Firebird (3rd & 4th Gen F-Body) with 9” axle housings: Compatibility: Detroit Speed torque arm rear axle housing: Differential: 31-spline Truetrac: Gear Ratio: 3.31: Yoke: 1350-Series: Ideal For: Pro Touring, high-performance street, and competition builds