[Jay S]

I am coming up with a 336 lb per inch spring rate with the numbers you mentioned. Is that a single flat tappet spring? Or is it a dual? A dual might work with a shim if that number was measure from a tester on the actual spring. I need more details on the springs. It sounds a little light unless I figured that wrong. I will double check my numbers.

I wouldn’t be concerned running that cam as a hybrid as long as you set the lash tight like I described. A nice lifter like a BAM with pin oiling would go as long as any HR lifter. They have bigger axles and larger .75” wheels, and are very rugged. All the HR lifters are .7” wheeled and have much smaller axles and bearings. Usually the Sat lifter are overkill unless you over spring it and run the lash loose. I have done $450 Doug Herbert (Morel) pin oiled lifters on hybrids and they have worked great for the money. Crower cutaways and Comps Endurex have been ok also. I think BAM is the top mechanical lifter though.

As far as what works as a hybrid, and what doesn’t, my general rule for mechanical lifters on hydrualic cams is to check where the tappet has 1* change in duration per .001” degree in lift on the closing side of the cam. On an Extreme energy Comp like yours that is about .006” tappet lift. If you multiply .006” tappet times the rocker ratio, that is the max ideal lash it should run when everything is expanded hot. The same pretty much holds true with a full mechanical cam. If the engine expansion creates to much lash and the lash is much beyond that hot lash it is adding to much acceleration to the valve terrain, and you really need as SR profile or a lazier HR profile. If you can set the lash tight enough cold that it can stay below that number hot after expansion, the solid lifters work well. If you don’t like it, it is a roller cam, you can swap any roller lifter back on it.