Anybody that was around class racing back in the 60-70's can recall the sound of the 'STOCK' cam, the only thing stock about them was the specs. Square lobes as Locomotion stated. Similar to running a flat tappet lifter on a roller cam, roller lifters weren't around at that time. Maybe that's where the roller idea came from.

it's ok to butt heads, just don't do it with a butthead