COMP Cams® Hustler™ Valve Springs for GM 603/604 and CT525 LS-Based Crate Engines

COMP Cams® introduces new valve springs for GM Small Block Chevy 603/604 & CT525 LS-Based Crate Engines for places where you can press the rules just a little bit further.

The new COMP Cams® Hustler™ Valve Springs are an improved version of the popular GM LS6 “blue” valve spring. They are based on popular GM part #12499224 and #12565313 LS6 springs but with 4% higher seat and open loads for better dynamic control, as well as an extra .020” of lift capability. Despite their improved performance, they look completely stock – they’re even painted blue so they are visually identical to the OEM springs – so they are an excellent performance upgrade in GM 603/604 and CT525 LS crate race applications with tight rules packages.

COMP Cams® uses premium wire and small batch manufacturing and processes to ensure maximum quality and durability over comparably priced options. Consider pairing these up with other COMP Cams® Hustler™ valve train components including a camshaft, lifters and pushrods.

Shop for parts:



About COMP Cams®

Founded in 1976 and based in Memphis, TN, COMP Cams® has become the automotive performance aftermarket’s “Absolute Leader in Valve Train Technology.” Our mission is to produce the highest-performing products possible, provide superior customer service and lead the industry in technological development.

Additional information about COMP Cams® and its products can be found at or by calling 1.800.999.0853 open M-F 7am-8pm CST. You can also visit us on Facebook (, Twitter (, Instagram ( and YouTube ( the full press release hereDownload

SHOP All New Products