Here's where the snag hit. On bottom is the Vortec head upgraded with factory LS6 valve springs. The LS6 springs hit coil bind at the installed height of 1.75-inches, so the Lunati PN 74881s on top were installed. Although the 74881s allowed full lift with no bind, their spring rate just wasn't enough to handle the gnarly Voodoo camshaft. Tune in next time for the fix and the full dyno report.