Stage 2 Thumpr™ 226/237 Master Cam Kit for GEN III LS 4.8/5.3/6.0L Trucks. Larger version of No Springs Required (NSR) Thumpr™ design for 5.3 & 6.0L truck applications. Ideal for more highly modified truck w/ headers, converter, gear, etc. The Stage 2 Thumpr Master Cam Kit for LS GEN III 5.3-6.0L provides an awesome idle lope in modified 5.3L & 6.0L trucks. Includes lifters, timing set, pushrods, LS6+ springs, retainers, locks, spring seats and valve seals.