COMP Cams is bringing the Thumpr camshaft series to the 2003-2008 Dodge 5.7/6.1L and 2009+ Dodge 5.7/6.4L HEMI engines. The new COMP Cams Thumpr NSR camshafts offer big power gains along with the unmistakable Thumpr idle lope, all without the need to upgrade valve springs.In the past, attaining a racecar idle sound meant swapping to a camshaft that sacrificed low-RPM torque. COMP Cams engineers have overcome this dilemma by delivering Thumpr camshaft technology to the modern Dodge HEMI engine platform. Thanks to optimized intake and exhaust lobes, the Thumpr, GEN III/IV HEMI enthusiasts can have a lopey idle without sacrificing the low RPM torque that street-driven HEMIs require.The Thumpr NSR camshafts for the Dodge GEN III/IV HEMI do not require a valve spring upgrade, while COMP Cams does recommend both an ECU tune and DOD deletion, as well as a phaser limiter for VVT-equipped GEN IV HEMI engines.