The latest blank I got here has the m4 cast into it, but SC1 almost looks like its stamped into it 180degrees round, it is a pre clearance blank, its a recent Engle supplied cam, they were getting there pre clearanced blanks from Scat for years [ only ones at that time that offered pre clearance blanks I think], not sure if they[ Engle] still do. Is it an Engle grind you have with M4 cast into it?
I have some other cams of varying manufacturer/grinder that have E4 instead of M4 that are older, I think that its just a batch number as they make 1000s at a time
I think up till this point you couldn't pinpoint a particular blank to cam grinder as we have had clay smith cams arrive on those same blanks and all scats cams are on them.
As for CWC, all I know is that's what Webcam use and they are hard and you cant use them with certain brand lifters and are not pre clearance but have a habit of bending when clearanced
cheers Richie