Comp hydraulic flat tappet thumpr cam and lunati microtrol lifters in a chevy small block, Comp claimed the cam was good after sending it back for inspection but replaced it anyway. @Newbomb Turk had checked the lifters before installing them and they were good. The second go around with new/same spec comp cam we couldn't get the lunati lifters so we went with some basic ones from howards cams and they actually ended up being diamond finished and were extremely nice.