Just fit it.
It fits.
You might want to make sure the diff ratio is the same as the one you take off, just in case some smart-arse changed it long ago.
First time you take it out on the road make sure no-one is close behind when you stomp on the brake pedal - unless you want their insurance to buy you a new rear crossmember and back door.
The difference in stopping power is very significant, which just goes to prove that the old drum brakes didn't do much all those years.
CharlesY