Jesel is the orignator of the modern racing belt drive system. They developed the belt drive system because Nascar racers were breaking timing chains in 500 mile races. Over the years, the Jesel belt drive system has only gotten more durable with improved features like external cam timing adjustments. Jesel is also known for other durable valvetrain components. They manufacture one of the finest shaft rocker systems and unmatched roller lifters on the market today. JEGS has the Jesel products you need at a price that can't be beat.