nytrdr24
+1y
is yours the older 13b non-turbo motor, and what tranny are you running....there are several options, but it all depends on exactly what you have in the truck now.....the 84-85 rx-7 gsl-se's rear is the same width as the trucks axle, 4.07 gears & clutch type lsd, if you still have the trucks tranny, using this one will keep ya from having to swap driveshafts, but you will have to cut the existing brackets off, weld new spring perches or link tabs on it, and have the axles drilled to a 5 lug pattern, 6 lug won't fit because the hat on the disc brake rotor is too small in diameter....
other options are a b2600 rear, and the carrier out of a 86-91 rx-7 that had the lsd in it, it will fit in the 26k rear, limequat had done this swap...but depending on what tranny you have you will need to either swap the driveshafts, or have one made or shortened, plus this swap wouldn't have disc brakes unless you adapted a set of chevy rotors & montecarlo calipers and some homemade brackets.
there is more info on mazda lsds here: