Premium Dual Valve Spring,OPTIMIZED from GM# 3859911 / GM # 3970627 in a Dual Design

105 lbs @ 1.950 300 lbs @ 1.420, coil bind 1.300” Spring Rate 358 1.480” OD

Heat treated 4140 Moly Hardened Retainers w/ hardened heat treated Locks

This kit allows for proper flat tappet valve spring pressures which is near impossible to get in 2024! We have tested many aftermarket springs for SBC and BBC Chevrolets and they are all that we have checked higher than their published pressures, which are too high to begin with. This is asking for flat tappet camshaft problems. 

Even the solid lifter Special High performance L78 396/402 and LS6 450hp 454 only ran 95-105 lbs seat pressure and not more than 310 open. So, running most if not all aftermarker springs in union with the poorly made modern aftermarket lifters, one can almost be sure to have cam/lifter failure at break-in or shortly after even when using correct zinc fortified oils and proper break-in procedures. 

We through years of testing using the genuine GM hardened face or hardened wafer lifters we also offer in addition to these spring kits you can almost be certain to avoid these problems that are plaguing most people running a flat tappet camshaft. We also offer the correct valve spring kits for small block along with cam and lifter kits for both small block and big block. Inquire for more information.