Well fast forward to today.
After completely forgetting how the hell all the bits went together, (Thanks for the workshop manual Don) I finally got my gearbox back together! I held it in the vise by the sump bung, and it does everything it should. With a bit of luck I'll get it back in this weekend. It's only going to be 9 degrees tommorrow. But the sun is supposed to shine. Perfect weather for lying on my back in the driveway with a weighty gearbox on my chest.
Since short 63's are so rare here, I think I may get another L4 box, and use the gizzards to rebirth the scattered remants of my 1st 63A. Then do a bellhousing cut and shut.