i made a special tool holder that bores the center 3 cam bores in line with the front and rear cam bores one at a time. maybe i ought to mass produce it for what's left of the BB mopars out there. i can tell you that a lot of the problem is sharp edges on the front face of the bores catch the bearing back and gouges the bearings going in, consequently distorting them during installation. aside from that, the cutters in the bar seldom take more than a few tenths from the bores themselves, but it's enough so i seldom ever have to touch a bearing after installion and the cams spin freely with two fingers.