on a roller cam the lifters need to be adjusted... and adjusted sorta often to have them tight enough, but not too tight.. its done with a feeler gage, sorta like gaping your plugs

after cam brakin, they should be rechecked.. after 500 miles (inital) then i'd check them every oil change..

google valve lash adjustment roller cam.. your cam manufacter proley has instructions on how they want it



hydrolic flat tappit have give in them, so you make them snug and add 1/4 turn or whatever it supposed to be.