B1600 rear axle in Mazda 1300
 

I have done a huge search without finding the answers...
My Old school project Mazda 1300 -75 do need a new rear axle.
It will be a 500hp sleeper when I am done!
I found a Mazda B1600 rear from 1977 on a scrapyard.
I would love a stronger diff or even LSD in it.
What would fit?