Expert????? do you want referances??? or can't you guys really see that the use of fitted lash caps that fit the tip of the valve/retainer/keepers will take the valve spring pressure load off the valve stem???if the lash cap doesn't push on the keepers, you are transmitting all the forces of the valve spring compression pressure waves to the groove of the valve/keeper and you will shear them creating havoc---also , on a road race car---more engine damage comes from downshifting than anything else than a poorly designed
oil system---one of the main things I enjoyed about karting with my boys was no lub system, no valve train