I think it depends on what you prefer and how you plan to drive it.
Do you want steep gears for wheeling and racing, or highway gears for lower RPM on the freeway?
In OD your 4.88s will turn into 3.66 effectively. You also have the benefit with the 4L80E you can lock the converter.
Locking the converter keeps the trans temps down as the converter makes the most heat. The trans won't care what RPM your engine is at on the freeway, no concern there.
However, with just 35" tires and a 496 brodix head EFI big block, it surely don't need 4.88s to be fast.
I find for my needs the 4.10s work well as I can put it on 4 LO and then they are 8.04:1 gears in the sand and still hit 75 MPH in 3rd gear. Low range also keeps my trans temps down. If I had 4.88s I would hit the rev limiter before the race was over in low range. If I put it in high range I lose about a truck length in the short race.
I do want a 4L80E instead of the TH400 as my converter slips and I can't lock it up and no OD puts me approaching 3K at about 70MPH, which means I usually only go 65-68 on the freeway to keep the RPM down. A lockup TH400 is way to expensive so I will likely build a 4L80E for it in the near future, then got OD and lockup, but it weighs another 100 lbs.
As for the ARB locker. I actually prefer a Detroit for what I do. An ARB is either open, or a spool. Which means when its locked, its solid, and when you go to turn it will fight you somewhat. You can disengage it, but not while its already under load. This is magnified in the front axle as I have seen situations where people couldn't turn the steering wheel because the front axle was bound up, and its too late to disengage while its bound up. The detroit does not get bound up like that.
With a Detroit, think of it like a ratchet. Either wheel can go faster than the ring gear, but neither wheel can go slower. So when you turn the outside wheel will disengage and turn faster, and then reengage. I have Detroits front and back. And when I turn in 4WD off-roading it doesn't bind up and want to go straight. I don't like when people say their Detroit locker will "lock" when needed for traction. It's actually the other way around. Its pretty much always locked, and it only unlocks one tire to allow it to go faster, but neither can ever go slower. This also means when you are turning a curve, and you apply throttle, it will reengage the other tire if the inner tire spins at all. Also, if you let off the throttle on a curve, it will go from driving the inner tire to braking on the outer tire. But it's predictable, does it every time.
The downfall is they have a little slop which is required to be able to "reverse" the ratchet when you put it in reverse, but I don't mind it.
I would not drive your rig in winter unless you want it to turn to rust here in the rest belt. But then you do lose the enjoyment in the winter.
Does your carrier have 3 or 4 pins?
It looks like that ring gear is very thick, it might be a special 4.88 gear for a different carrier. Does a 14 bolt even have different carriers like a 10 or 12 bolt? I forgot the answer to that. I haven't opened my 14 bolt other than change the gear oil once since 2003 when I put the Detroit and new seals in it. Now that I said that I will probably brake something.
