It is possible to run solid flat tappets on a hydraulic flat-tappet cam and even mechanical roller lifters on a hydraulic-roller cam. Putting solid lifters on a hydraulic cam will gain about 500 rpm ...
"Bullwinkle, that trick never works. Why don't you figure out how to make hydraulic roller lifters survive big spring pressure." "Huh?" Like Bullwinkle, hydraulic roller lifters get no respect. It ...