Extreme application belt for high rpm and high compression durability. Infinitely adjustable Vernier sprocket for absolute timing accuracy. Unique belt idler system reduces flap throughout rpm range. Designed to absorb crankshaft harmonics to guard against performance robbing valve train instability. Utilizes a unique Camshaft thrust adjustment system without shims. Includes double lip Seals for long life and maximum crankcase vacuum. Ideal for Serious street performance and race applications.