Ford 9in Pro-Spool Light Weight Steel 40-Spline

The Ford 9in Pro-Spool Light Weight Steel 40-Spline is engineered for competitive drag racing and high-performance applications where traditional differentials cannot handle extreme torque loads. By eliminating the internal gears of a standard differential, this spool ensures that power is delivered equally to both rear wheels at all times for maximum traction. It is an essential upgrade for racers looking to shed rotating mass while maintaining the structural integrity required for high-horsepower launches.

Constructed from high-strength steel, the Ford 9in Pro-Spool Light Weight Steel 40-Spline features a Pro Series design that balances durability with a minimized weight profile of just 8.9 lbs. This lightweight construction reduces parasitic power loss, allowing for quicker acceleration and improved throttle response on the track. The 40-spline internal configuration provides a significantly larger surface area for torque distribution compared to standard axle counts, preventing failure under extreme stress.

This spool is designed specifically for use in aftermarket Ford 9-inch cases and requires compatible 40-spline axles to complete the drivetrain assembly. Users benefit from a predictable, locked rear end that eliminates the unpredictability of limited-slip mechanisms during high-speed passes. Whether you are building a dedicated strip car or upgrading a heavy-duty rear end, this Strange Engineering component offers the reliability and precision needed for professional-grade performance.