As you know, roller cams have a much more aggressive profile, when compared to solid lifter cams. The roller cams faster ramp speed requires a higher valve spring pressure to keep the lifter on the cam. The higher spring pressure means that the cam shaft needs to be made of a tougher material than a solid lifter cam. Also the roller cam's roller contact point does not spin laterally across the cam lob surface the way a solid lifter does, again requiring a tougher material in the roller cam as the spinning action of a solid lifter allows the lifter to ride on a film of lube oil, while the roller on a roller lifter basically squeezes away the lube oil in front of the roller to cam contact point. This does not mean a solid cam re ground as a roller will not function, it just won't function for many miles,, may work for several runs in a drag race only application. Or, have Oregon grind the roller using the proper material-steel billet.
