Out with the old, in with the new. Once the Edelbrock 2108 cam showed off its stuff, we couldn't wait to throw the bigger cams in there. We noticed that the Edelbrock cam was "back-halved," meaning it used steel billet as a core, but with a softer oil pump drive gear sandwiched onto the rear, whereas the COMP cams were all iron billets. Both designs were perfectly compatible with the factory oil pump drive gear mounted in the block. Two roads to the same destination.