By SM are you talking about Smith Machine in Ceder City Utah? If so here is my .02. One of new lifters has had bottom come off and destroyed engine 1st pass. Three more out of the the same set refuse to pump up and the plunger just lays on bottom spraying oil out top everywhere! I run plenty of spring pressure, work on rocker geometry carefully, don't adjust them too loose.... I have been building engines 50 years. Quality control on cups is better than Schubeck, I don,t have to hand fit pushrods to each cup anymore. Fortunately with problems with Schubeck, he would fix or replace them......Smith is always willing to sell me a new set for retail... of course. I need to find about new tool steel lifters
