742 8-3/4 Sure Grip Rear

I set my SGs to 120 minimum, for a streeter
If the splines are misaligned, you can anchor the other sidegear by installing the axle and locking it from turning. Then go around to the first side and rotate this axle a tiny bit,(yes with a bar,lol) until it slides into the clutch. Then lock this side and go repeat on the other.
Of course for this to work, the axles and splines have to be at least long enough, to get into the clutches,lol, and the driveshaft must also be locked.