legacycentral bbs

I'm trying to mount my extra ej22 on an engine stand and I can't figure out what the thread size is tapped into the bell housing. I'm assuming that its the same thread on both transmission side and engine side.

The studs on the bottom? They're 10 X 1.25. I just threaded a 12 X 1.25 nut on there, and it threaded on perfectly, but was loose.