The taper on a flat tapped lifters keep the cam from traveling forward or back, but a roller lifter has no taper. I run a solid roller cam in a street strip car and I used the nylon button to get about .005 travel on the cam. I have been told some cams will try to travel so hard they will mushroom the button, The is a needle bearing button available. I just change my timing chain and the nylon button was fine after maybe 200 runs and some street driving. The cam is .646/646 solid roller with 266/272 duration @ .050. The lash on a solid roller must be checked often to avoid disaster.
