From memory (vague), the GM Gov Lock was a near drop-in for Cruiser diffs....IIRC, there was some minor machining of the ring gear seating diameter required to bolt it up, and perhaps some machining of the side gear bearings.
Common mod in the "early days" when there wasn't a plethora of Detroits, EZ-Locks, ARB's, etc available to purchase.
(heh heh - I used "plethora" in a sentence - heh heh)
The gov lock is a cool idea, but they don't last long with big tires. The work as a LSD until the side gear slip gets to a certain speed and then it locks up. This sudden lockup along with the inertia of big tires results in BANG-POP. Fortunately the cracked carrier in my Suburban tow rig held together long enough to get home where it grenaded just backing out of my driveway. The spider gear shaft was sticking through the cover and it looked like the rear end was smoking a cigar.
If you don't have tires bigger than 33s and you go easy on the skinny pedal I say run them until they break. Might be good to carry a spare 3rd member on the trail.
I dismantled the 3rd member (after checking R&P mesh patterns, which were excellent).... here's what I found:
The Lmited Slip carrier had the bolts holes enlarged and shifted slightly inward, to allow the carrier holes to line up with the ring gear holes.
There were also shim plates about 1/4" thick between the carrier and the ring gear (I'm assuming to allow the R&P to mesh such that the bearing preload nuts would be adjusted to approximatly the same depth)....
Sure looks to me like this Limited Slip carrier belongs to something other than a toyota...
I did not press the bearings off the carrier as it is going to be a big paper weight....
The outter races are Koyo 17831-N... Is this the stock Toyota bearing?