[Tom Goldman]

I know several racers using them.......One experianced a failure in 60 runs, the other two have hundreds of run on them.
I would not use them unless the lifter bores have been squared.
The failed block had not had the lifter bores done and you could see the outer edge of the roller wheel was flaking before it locked. ...When he checked it with new lifters and prussian blue, the contact was showing heavy on the same edge that was worn.
While this might be true for needle bearings as well as the solid bearing, there is probably less forgivness in the solid bearing.