Extensive engine dyno testing at Lingenfelter has produced some of the best street camshaft profiles available for the LS7 engine. The Lingenfelter GT21 series camshaft was designed to produce excellent power with a rough idle for 427 CID LS7 ZO6 Corvette applications with the six speed manual transmission. The GT21 camshaft is designed for daily driven C6 Corvette ZO6 applications and is the same camshaft included in our LS7 660 HP engine packages. This camshaft will have some driveabilty issues at lower RPM's. This camshaft can also be used in other 427 CID LS7 cylinder head and intake applications with manual transmissions or automatic transmission applications with a loose torque converter. Spring & retainer upgrades are a must with this camshaft. This cam can be installed in LS7 engines without modifications to stock pistons. All Lingenfelter camshafts ground by Competition Cams to Lingenfelter pecifications on induction hardened cores for exceptional durability and long life.