The main caps have to be machined to a critical dimension on a mill or surface grinder. The girdle has specific and detailed instructions included with it. (RJC girdle, anyway) The block MUST be line HONED (not bored) after the girdle is torqued in place. (both main bolts/studs AND pan rail bolts MUST be torqued prior to line hone.) Just follow the included instructions carefully. I hand sanded the pan rail with a sanding block to get a .005" pull up/pre-load. It really didn't take that much time to get it "perfect". Probably about an hour of sanding, total.