Mike,
I am trying to find them, as far as I know they one shattered through maybe incorrect valve adjustment, and the other was a Camaro that had them but failed and the guy vowed he was staying with a flat tappet normal lifter!
I have spoken to my builder and the decision is either Jesel solid roller lifters or the Ceramic Schubeck, as I am not convinced that a properly setup roller with not to high spring pressures to go to 7200rpm max this setup should be reliable with the Shelby block
oil system, also with Schubeck lifters the only point on those for me at the moment is the hp loss compared to the roller, but having said all that the car is a road racer and will see more road miles that the track by far!!