Depends on what type of engine and what size core and lifter and how they are prepared and broken in. We used like 160 seat and 450 open on normal SBC .842 that were lifter trued and broken in very well with lower pressure. This was on normal Comp and Cam Motion cores and with regular lifters. Idle was kept high like 2500 or more for drag race usage and cams were very smooth. We use that much all the time of Ford Windsor stuff in circle track as well and have never had a cam go flat so far but they are a bigger core and have bigger .875 lifters.