The point is with the rev kit one does not need excessive spring pressure at the valve,which then is redirected down the pushrod to the lifter, creating a lot of pressure on all the inline components. Just as you said with the retainers and clips from Edelbrock, If all that they are controlling is the valve ,there is no lifter bouncing against a rising valve causing the locks to come loose. So I get the shafts and girdles... but that is overkill again. The rev kit ,Yes, was primarily for race only engines, but when one looks at the whole picture I think the benefits are many. I can tell you that with the mechanical lifters (rollers) that I have, I can hear that the only play is at the rocker( also rollers), at which a little play is absolutely needed, unless you run hydraulic, at which point without the rev kit the lifters and cam still are going to take more of a beating than with the kit. Hey ...what can I say ...I think the rev kit works great!!!
