Installation of Rebuilt Original Ignition Switch

[Brentwood Bob]

I don't see how you will be able to install the pop out with out removing the distributor, and I would drain down the antifreeze first. The cable should only be turned in enough to contact the lower plate. The distributor can only go back one way unless you are very creative and manage to jam it in.
I also would consider retorquing the head if you know the history of the engine. That can be problematic too, but if you loosen the head nut for the clip it will need torquing when it gets reinstalled. But you already know all of this since you have les's manuals.