Flat tappet to solid roller...

here's one of the places I saw it...

Solid Roller Cam Setup - Popular Hot Rodding Magazine

It even references periodic inspection of lifters, even with the new premium parts

"Shane also suggested that regular maintenance could help avoid problems: “As far as maintenance, I recommend watching the lash. Over time, the valvetrain will settle and the lash will not vary much. If you notice the lash on one or more lifters starts loosening up more than normal, that’s when I would recommend pulling them out and inspecting them. If you notice play or roughness when working the bearing, send them in for rebuilding.”