GM has recently made available "composite lifter holders" for the Gen I factory roller blocks. It is similar to what is used in the LS-1. What it is is a plastic (of some sort, I assume) tube that sits in the valley, and the lifters run up and down inside them. The trick is, that when the rocker arms are completely backed off, the lifter will stick in this tube. One complete revolution of the cam and the lifters are all captured in the "up" position. It allows for cam changes without removing the intake manifold. It sounds like a pretty neat idea. I'm doing a cam swap here in a month or so, and am considering installing them. $10 each - cheap. Does any one have any negative experiences with these on LS-1's, or see any potential downside? Thanks!

PS See the latest Car Craft p98 if I did a crummy job explaining them.