Roller cams require a steel, not cast iron core. Schneider says a cast iron roller cam will fail in a matter of minutes after starting the engine. They've tried it! The only forged steel cam cores for stovebolt engines are for the 216 and early 235 engines, and they have the small diameter bearing journals. It would be possible to press sleeves over journals and machine/grind them to 235 size, but the roller lobe shape would be limited by the 216 lobe size. By making a completely round lobe the diameter of the #3 cam bearing, the cam grinder would have a much larger core lobe to work with. Comp Cams uses a similar procedure to grind cams for NASCAR engines, with a solid steel billet with a distributor drive gear machined onto one end. A few years ago when I got a tour of the Comp factory, that billet sold for $3500.00- - - -before grinding was done! Stovebolt cams present a problem, because the drive gear is in the middle of the cam, not on one end. Hence the necessity to use two billets, spliced onto a gear salvaged from a junk camshaft.
Jerry
