When using real high lift roller cams in the 292 engines along with the real long pushrod length in it, you can end up with a real flimsy pushrod because of the extreme valve spring pressures that are associated with it. This setup effectively shortens the pushrod length and makes for a more ridgid and less flimsy pushrod. The mini lifter floats inside the tubes shown. So you are effectively shortening the pushrod by the same length that the mini pushrod is. However, using the correct type pushrods to start with eliminates the need for this kind of set-up.
