Procomp Electronics 9 Keyway Double Row Timing Chain Kits are CNC Machined from billet, Engineered for accurate, consistent timing, faster acceleration and top-speed performance. Trust Procomp Electronics to give you timing sets that will deliver accurate, reliable cam timing. Our billet steel true roller timing sets have rugged double-row, true-roller chains teamed up with billet steel crank and cam sprockets. The crank sprockets have multiple keyways, which allow you to modify your cam timing.