It's not a big difference. I quit using two sets of bearing, and just put my own groove in the lower shell. When I was using two sets of uppers, I modified the notch in the cap. The Mopar Performance book says to file the tab down on the grooved lower shell, but I never liked doing that. If you left a high spot, it is possible to deform the bearing, and if high enough, have bearing/crank contact. Plus, then you have to do it any time you replace the bearings. When modifying the notch in the cap, it is once, and done.
