Perhaps because the battery has been relocated, a PO has used the alternator terminal instead of the positive battery post as the common meeting spot. There appear to be a number of large cables converging on that terminal. Maybe that's normal for later alternators (E21?), but my thinking is that if he fiddled with those and the car started, there may a flakey connection there, regardless of how the wires got there. Cleaning ground strap from block to chassis should be part of the connection cleaning process, but I think he'd have seen evidence of something else serving as a ground.