9in Gear Full Spool 5.14 Ratio New Center Section

The 9in Gear Full Spool 5.14 Ratio New Center Section by PEM is purpose-built for high-performance rear axle applications where maximum traction and consistent power delivery are non-negotiable. Whether you're building a dedicated drag racing platform, a street strip hybrid, or a heavily modified off-road machine, this full spool center section replaces the factory differential to eliminate wheel slip and lock both rear wheels together under acceleration. It's engineered for enthusiasts who demand uncompromising traction control and are willing to accept the handling trade-offs that come with full-lock differentials in exchange for raw acceleration authority.

At its core, the 5.14 gear ratio—a numerically steep setup—multiplies engine torque at the wheels, delivering aggressive acceleration off the line and superior low-end response for vehicles running moderate power levels or requiring maximum mechanical advantage in weight-limited competition classes. The full spool design eliminates the differential action entirely; both wheels are mechanically locked, ensuring zero slip regardless of load or traction conditions. Weighing 72.4 pounds and measuring 15.5 x 15.5 x 21 inches, this new center section is a complete drop-in replacement compatible with 9-inch Ford-style rear axle housings. The robust construction withstands repeated launches and sustained high-torque loads typical of turbo applications, superchargers, and high-displacement naturally aspirated engines.

This center section is ideal for dedicated track-only vehicles, bracket racers, and serious off-road competitors who prioritize traction over street manners. The 5.14 ratio performs best in applications targeting 60–100 horsepower gain windows or vehicles already running significant cubic inches; it will cause aggressive tire chirp and understeer on street applications without prior planning. Installation requires lifting the vehicle, removing the factory center section from the 9-inch housing, and bolting in this PEM assembly—a straightforward job for any mechanic with rear axle service experience. Confirm your housing accepts 9-inch Ford architecture and verify gear ratio compatibility with your engine, transmission, and target RPM range before purchase.