I have an '84 GS, which is a large axle drum brake car of course. I have an opportunity to get the center section of an '83 GSL with the LSD unit (sadly no disc brakes) for pennies on the dollar. Is it possible for me to open up the rear end and simply swap out the diff itself, despite the different axle diameters, or is it a different unit altogether? LSD is more important to me than disc brakes at the moment. I searched this one and couldn't find an answer, as most seem to just swap the whole axle, and I don't have that option.

 

Never mind, finally found it in the archives, it won't work. Mods feel free to close/delete.

 

You can swap in an LSD from a Gen II, 3rd Gen or Miata, I think. Why I'd prefer to go to the big bearing rear end.

 

^Has to be the LSD from a NA FC (not all of them had LSD so not super easy to find...), the T2 and FD diff's are 8" and won't work.
Someone correct me if I'm wrong but the Miata has to be the 1.8 liter, I thought I read somewhere the early 1.6's were a 6.5" diff....

 

Whoa, interesting. Has anyone done it? Definitely gives me somewhere else to look if true...

 

Both NA FC and Miata diff's have been swapped into FB's yeah. I personally haven't, but I know DJ55b has a Miata torsen in his FB, and I'm sure plenty of others on here. Just make sure its the 7" diff

 

I believe Hyper4mance2K was running a Miata Torsen as well.