If you look real close at Figure 16 you can see he chopped the end of the bolt off. Upon reflection, I would have just turned the bolt around so the nut was on the outside. I expected he'd apply some heat to the collector and pull it in a bit. I've seen them do that before. I'll have to pick up a new bolt and re-do it myself, not sure I like the idea of the shortened bolt.

***Actually, looks like he took a section out of the collector and re-welded ...AND cut the bolt off.