Have you checked the cam to see if it is flat? I see online that they sell flat lifters so possibly your lifters are reusable . An interesting subject and i hope someone with actual experience will reply.

@steve-d Thanks for your quick reply.  We checked with aftermarket manufacturers (Melling etc) and they show the crown in their spec sheets.  The matching camshafts are crowned also for the rotation of the lifter.  They claim that the camshaft will not last unless this method is applied which is the way (they claim) the factory manufactured them.  I am also asking for a friend but I am being asked to grind the originals if he cannot locate a set.  So I am trying to configure my Sioux machine to perform this operation.