the three bolts that physically hold the distr. housing on. they are slotted to allow clockwise and counterclockwise rotation of the distributor. turn the distributor until the heads of the bolts are pretty much in the middle of the guide slots. if you go out and look you'll see it pretty easily. one of the guide slots is at 12 oclock, one is at like 5 oclock, and the other is at like 7 oclock.