I'm lookin' to install a full floater in my '73 FJ40, but what unit should I use. What vehicle should the donor be and what year, and why? ... or why not? ...one way of the other, disc brakes are a must.
If disc brakes are a must, I would suggest finding a full floater off of a later 70 series with disc brakes. The perches will be a *tad* bit off for putting it under a 40 series, but it wouldn't take much to fix that... Plus, you'd get the park brake on the axle. Otherwise, just go with a later 40 series full float and add disc brakes your self from a kit.
I would talk to the guys at G&S Cruiser Parts about gettin' one of the 70 series ones.
When I first started looking into lockers, I wanted something other than the norm that was out there. Also, I wanted a selectable locker, but I didn't want the air locker. Anyway, in my searching, I came accross the Toyota cable lockers and the electric lockers. I started trying to find the cable lockers 'cause I thought they might have less chance of failure (whether or not that is true, I don't know 'cause I don't have both). Anyway, finding the cable lockers proved to be a tad bit harder to do, though I did end up finding a great place that could get them. In the end, the determining factor for which route I took was price.
As for the electric and cable lockers being better than air, I couldn't say as I don't have personal experience with them all, but I have heard about the o-ring problems and don't care to experience them--especially for the price of an air locker system (including install ...).