HPDE valvesprings
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Joined: Dec 2004
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From: Casselberry FL
HPDE valvesprings
Hey guys, I'm building a 416 LS3 engine that hopes to see intermittent HPDE usage and weekend driving. It's going to be a hybrid Gen4 bottom end with the AFR 245 LS1 heads setup. To take advantage of the head flow, I'm expecting the gross valve lift to be near .650", and I'm told the net lift should be near .620-.630". On street engines I've always preferred a beehive, but it looks like the max supported lift for a beehive is .660". The springs on my short list are PAC 1276X, 1205X or 1222X. Any direct experience and reasoning to choose one over the other? Or another model?
Oh, and while I'm here, thoughts on Yella Terra Ultra Lites for the same? It looks like I need to use YT5132 or YT5123valve cover spacers to be compatible with OEM valve covers. Concerned about leakage and OEM thread engagement, and don't want to lose the OEM PCV baffling.
Thanks
Oh, and while I'm here, thoughts on Yella Terra Ultra Lites for the same? It looks like I need to use YT5132 or YT5123valve cover spacers to be compatible with OEM valve covers. Concerned about leakage and OEM thread engagement, and don't want to lose the OEM PCV baffling.
Thanks
Last edited by JimMueller; May 24, 2026 at 07:07 PM.
