Easy one

So if I’m understanding this correctly. And please correct me if I’m wrong. The flat tang on the distributor fits in th already installed intermediate shaft. There should be only two ways to put it in, right or 180 degrees wrong.
MRO
The distributor yes.
The intermediate shaft, no. The feared shaft will fit in on any position. When installing the intermediate shaft into the engine, after the cam shaft is in, the distributor can be 180* out of sync.

You want the rotor tip to point to the number 1 piston. Most forward to the nose of the car drivers side.

An excellent book to have on tap is the “How to Rebuild or How to hot rod your small block Chrysler.”

These (Ether book) are excellent to rebuild your engine from.
Extremely recommend book to own, read and rebuild from and always have on tap.