DLC Coated Lifters

If the cam taper and lifter taper are correct there should be very little friction. The lobe spins the lifter . It doesn't slide across it.

On a mopar small block 8 lifters spin one way and the other 8 spin opposite. Due to the cam having a thrust plate there is no need for the lobe to push the cam rearward using 16 lobes tapered in the same direction. Most all of the cam grinders are aware of this some are not. beware.