The PAC Racing PAC-1238X-16 is the highest-rate dual valve spring in PAC's 1.274 in. LS spring family, built for solid roller camshafts pushing up to 0.750 in. of valve lift. It is a direct replacement for other round-wire 1200-series springs in the same diameter but carries a heavier rate than even PAC's 1208X, making it suited to aggressive high-RPM or forced-induction LS combinations where a lighter dual spring would float.

PAC Racing Springs PAC-1238X-16 RPM Series Dual Valve Spring Set Features:

• Fits GM Gen III/IV LS engines running aftermarket cylinder heads with a 1.274 in. dual spring pocket
• Rated for solid roller camshaft profiles up to 0.750 in. of valve lift
• 1.274 in. outside diameter, round wire construction, 0.985 in. maximum coil bind height
• 600 lb/in. spring rate, the highest in PAC's 1.274 in. round-wire LS spring lineup
• Built from PACaloy super clean wire, heat-treated in-house, and finished with PAC's multi-peen and Nano-Peen processes for extended service life