COMP Cams Belts - Timing, Accessory 6300 COMP Cams Hi-Tech Belt Drive Systems come with an extreme application belt for high rpm and high compression durability. They feature an infinitely adjustable Vernier sprocket for absolute timing accuracy. These belt drives are best in serious street performance and racing applications. Hi-Tech Belt Drive for Chevrolet Big Block w/ .400" Raised Cam Location COMP Cams Hi-Tech Belt Drive System for Big Block Chevrolet, .400" Raised Cam COMP Cams Hi-Tech Belt Drive System Che