never really questioned it but ever since i can remember mopar cams were always refered to as a purple 509cam (292/509). a purple 484 cam (284/484) they did like stated above have that one that was always refered to as the hemi grind 280/474 if i remember correctly.
Even before the purple cams, they were Direct Connection cams when Racer Brown ground them all, they were still referred to by lift. I have a Direct Connection book around here "somewhere".