The plot sickens, the L series spigot is bigger than the a series one. I'm going to have to either swap the one off my old box, or turn down the L series one off the donor box. I also found the bearing cups on the cluster bearings aren't flash. So my quick bell housing swap has turned into an overhaul. No biggie. My old box is beyond repair. I'm thinking that some of the bearings I replaced when I patched it up last time might be reuaseable.