Random AC question

If r12 works well then don’t disconnect. Remove ac from top side but leave connected and remove engine from the bottom side of the car.
Your ac system with r134a will not be the same. R12 is crazy expensive and letting it just fly is stupid for all the wrong reasons.

Plenty of articles in search feature to read up. Your car your way. My opinion is leave it sealed if you can.
Syleng1