Wow...Well thought out answer...Really..
An Open knuckle front end will eat debris. That goes without saying...I must admit that I run non stock Heavy duty U joints in all my axles.
and have blown a few over the years. Even the outers . But only in a bind .
Maintenance is KING..........If you ignore any part it will fail.
 I'm sorry. While your statement that a Yota will hold up as well as a D-30 is conjecture.
 Unlike the Yota. The 30 was designed to handle the HP and TORQUE  the PO requires...Has the track record to prove it. Is less than half the cost, is the correct width, same steering geometry, many more gearing options, tighter steering radios than a barfield, and if unsprung weight is an issue , don't modify your Zuke at all.

 As to how and where we wheel . I live in Oregon , Do I really need to explain??? We are lucky enough to have it all..
I don't want to seem like a Yota hater here.
 I own a 78 FJ 40, as well as several Jeeps and a Zuke . And will defend The FJ to the wall.
 It's my favorite ride. It's also the most expensive rig I own, (next to a Patrole I have been restoring for about 10 years) and maintain....Parts are extremely expensive , And sometimes hard to find...
 Jeep parts on the otherhand...NOT SO MUCH...
 By the way I have friends and clients that break things to...That's how I've staid in business for 35 years......

I try never to give bad advice . Or advise just based solely on what I do, or have done to my rigs...
Rather on the needs of the PO in question..based on cost , durability, ease of installation , serviceability,  fit. And then experience.
 But never ever based on conjecture. Gotta go to work now. Been fun......Boxcar...
 
 

Nice sarcasm.  I also like how you automatically assume that nobody I knows how to take care of their rigs, all we drive is junk heaps and do nothing but mall crawl.

Well, I might as well look up some base stats:
Dana 30:
Ring gear diameter = 7.25"
Axle shaft diameter = 1.16
Inner Spline = 27 spline

Toyota:
Ring gear diameter = 7.5" or 8"
Axle shaft diameter = 1.24"
Inner Spline = 31

Smaller axle shafts, ring gears and spline count are all hallmarks of a stronger overall axle.  I concede the point to you.

Moot point anyway, he is looking to stick with the 5.5 to keep his wheels.  Either axle with upgrades should be able to survive a 5.0 and 33" tires.

Never occurred to you to check the Quality of the steel that these axles are made from???
1960 s and 70 s American made steel vs.. 1980 s Japanese recycled steel???
 Check the torsional loads designed in to either axle in question...
 If axle size and ring gear diameter are that important to you, I have several AMC 20 s in the scrap bin behind my shop you can have for the scrap value...........
more stats for your vault:
YOTA AXLE--- 55-58" wide
centred diff. (rear)
6 lug
low steer.
Jeep narrow track D-44 (rear)
50" wide.
1970 and earlyer - same offset as Zuke
5 on 5.5 lug.
 D-30
50" wide
Same offset as Zuke
5 on 5.5 lug
High steer.
 Steering joints are commonly overlooked by many people until they fail....
Never called you a " mall crawler..or a dumb A.. Don't get so upset...
 Look Drone . I'm not here to beat up on your ideas . But give advice and learn at the same time.
Yota axles are good solid units. Just not the best conversion parts for the Zuke.
 If your running Yota s...Cool. I'm sure you love your rig....And I'm sure it works well....
The cj conversion can be done at less than half the cost / same or better results / Leaving the PO with more $$$$ to spend on the Zuke on another part of the rig...Nuff sed...Boxcar...

 

Actually, I run a Sammy axle with Double Toughs from Trail Tough.  With 950cc of power pushing out a mighty 45hp of raging stock 1984 hp I didn't really have to worry about breaking things to much.    Building a IFS Tracker currently, it will be interesting to see how it works out.

But if I was starting from ground zero I would have gone with Toyota to start with, one of the down sides of building a rig one piece at a time without a lot of background first.  A lot more of the same parts front and rear and a lot of aftermarket support.

As for the torsional loads, that is actually a pain in the ass to find.  I found around 5000 for the stock Toyo shafts from some Bobby Long testing, but couldn't track down anything for the 30. 

I do agree with you about the price though, a Dana 30 is going to be a world cheaper then a Toyo setup and a lot easier to find.  A bit more work to get going since you don't have the aftermarket support but it should work fine.  And as you pointed out, the 5x5.5 bolt pattern saves some more cost.

There was a fun thread where someone put a Dana 30 under a Tracker, would have to dig to find it.

You could have some real fun with your front axle.  Check out this one from an old Zukiworld article:

These are all parts that pale in comparison to the fully custom scratch built front axle that uses the Sidekick rear 3rd member, and ARB with custom 27 spline sidegears which couple to Superior Axle Dana 30 Cromoly Axles. Knuckles are of Dana 30/44 design with adapters to use the Sidekick Disk brakes. Hi-steer with custom Drag link and tie-rod. Spindles are Dana 30, Warn Premium Hubs get the power to the ground.

http://zukiworld.com/month_110103/feature_saskick_wmovies.htm

Kind of goes away from simple swap though. 

For after market support on the Dana's you must think Jeep. Try Quadratech , 4WD Hardware, 4x4 Parts, Novac, Jegs, Advance, BJ's,, Summit . ETC....
 Wow. Must of taken a year to figure that drive set up out ...Cool though...
 Back to aftermarket support:
The Dana 30 design was first used in the 1930 s and is still used today..Plenty of tech support and parts out there...
Never done the Track Kick thing. I should , There cool , Just to many toys now. Maybe Ill get lucky and a client will want one built.....START THE LIRNING CURV ALL OVER AGAIN.... Fun...Boxcar...

well i went out this weekend for the first test run. I gave her hell, i was trying to break some axles. but she came back in one piece.. Yes anyone can break axles if you really dont know how to drive. but if you use common sense and dont let your tires hop then you got a better chance.

I know i have all the tourque and hp i need, but all i did was ease up to a mud hole drop her in 4low, 3 rd gear and let her eat.. now let her catch on  a hard root or rock and slam the throttle then yeah its gonna snap

I was reading your other thread. Sounds like you had some fun........
 As I posted earlyer: Didn't think the stock T case mount would last.
There are several relay well designed new mounts out there for reasonable $$$$
 I'd check into one...
The TSL's are a great choice. All that new bight is going to transfer torque to your running gear...Be carefull...
Glad you had fun with it...Boxcar....

thanx boxcar. yeah im just looking to have fun right now untill i get a few rides under her. I looked at all the transfer case mounts and they all look good,but for that price i can make my own.. we own a full pump facility which gives me the previlage to machine shop and welding. as we speak my welders are adding 2 new points to anchor to the t case, also all the brackets are being removed and 1/4"  thick angle iron is being installed to replace them. should help significatly. since my t case had to be moved back for the motor and tranny upgrade the guys that welded the new brackets did a horrible job, all the welds were 3/4 broken( i dont trust any of their welds not).  Which is why all my motor mout welds are being grounded off and welded properly just to be safe...

Gotcha.
 Got to love the bird shit some think are welds....Boxcar...

My favorite design so far is the snatch from Zor.  Mainly because he moves the mounts away from the stock position, making it a lot easier to drop the transfer case.  If I was building one I would go with a similar design.

It's never fun to go through and fix a mess somebody else made.  Good luck! 

i made 3 brackets that bolt on to the t case in 6 points, then hooks to both frames... shes definatly not moving now

Not exactly true.... I had one of those hopped up 78 258 6 cylinder CJ7's with a cam dynamics cam, head milled  / polished, offenhauser 4 barrel intake, Holley 650, with split manifold headers. Mine had flipped axles (that is what the called a Spoa then) with a 3" Rancho lift and 15x38.5 Ground Hawgs.

I never had any troubles with the axles nor did anyone I ever met. However on several occasions the wheel differential cross shaft would break and leave a person stranded without any movement.

I also broke the ears of of a few yokes and crapped out some u-joints. The later two died from grunt and flex from the driveshaft. Once I put  saddle straps on the shafts to help eliminate some of the flex I had no more problems...