How strong is Ford's IFS? (Dana 44)

Kid witha 89

I have an 89 Bronco and I'm looking into some bigger tires and lockers. I've been checking out some lunchbox style lockers but I've been told that some differentials can't really handle them. My question is: Can I put a lunchbox locker in a Dana 44 and what size tires can it handle? (Assume that I'm going to abuse this thing a little bit)

TTB Broncos have been built for prerunning for decades, a lot of guys will throw on 37s and there's even a couple 39s out there. That usually involves chromoly axles and some high quality diff gears, plus a custom built Ford 9" in the rear. Sometimes they convert to 2wd for wheel travel (desert guys are weird haha). Personally, I've only ever had 33s on my '88, but when I was looking into it the general rule of thumb is 35s before you need to start upgrades to the shafts. If I remember right, it also has a u-joint tucked in there, so I feel that the locker will strain that before the shafts. Honestly, finesse on the go pedal will save parts or break them far easier than tires that are too big.