Sonnax high clutch hub 28304 is designed for the extra duty requirements of drag racing GM Powerglides. Machined from a high-quality medium carbon steel forging, this high clutch hub accepts five friction discs for the added load capacity needed in high horsepower racecars. All splines and thrust surfaces are precision machined to exacting tolerances, and the unique lube hole pattern is designed to reduce drag on the friction discs in low gear. The hub also features five lightening holes to reduce rotational-weight without compromising strength.