USA Standard Spool For Ford 9in / 31 Spline - ZP FSF9-31

Installing a quality USA Standard Gear spool is a cost-effective way to get 100% lockup. Installation is easy as they install in place of your differential carrier assembly. Each USA Standard Gear spool is made from high-quality 8620 steel and heat treated for additional strength. A spool is an outstanding choice for dedicated off-road and drag racing vehicles only.