PEM Racing Ford 9 in. Center Section Assemblies are designed to help you get your ride's horsepower to the ground, helping you accelerate down the straights. PEMcenter sections feature a nodular iron case, pinion support, yoke and competition ring & pinion with a steel lite full spool. Manufactured as a 28 or 31 spline assembly PEM Racing has the right Center Section to give your ride reliable weekly performance.