I'm over the hill and it has been nearly 50 years since I owned my BSA Gold Star. In the 60's, the rage for engine modification was titanium connecting rods, teflon buttons to retain wrist pins and roller followers from cams.
The rollers were only important to cams employing push rods. I would guess most high performance bikes use Overhead Cams. But on the standard cam configuration, are roller followers still available and used?