72 manuals came with a 3.36 diff. Automatics came with a 3.54. If you have a stock 4-speed, jumping to a 4.11 diff will definitely help torque off the line, but will shoot your already high freeway RPMs even higher. They're usually put in by people who also put in a 5-speed.
R200 4.11's came on 85-86 Turbo 200sx's. They're a little hard to find, but they are out there. You also need half shafts, and mustache bar off a 280Z to complete the swap.
R180's came in non-turbo 200sx's at around the same time, but the diff requires some internal modification to accept the 240Z half shafts. Search the archives, there's a few posts about this. That's what I have in my '72 along with an '82 5-speed. Very nice combination!