Is your 46 Burb a 1/2 ton? Plan B for axle swap. Keep your original axle and diff housing. Replace the 'pumpkin' with a 54-62 open drive shaft pumpkin. Set axle pinion shaft angle and weld axle mounts. Your good to go.
I did my '50 3100 this way. It has a 3.90 rear, and my rear tires are 28.66" tall (according to the tire page on Discount Tire's website). My T5 has a 0.76 fifth gear, so I run 2,300 rpm at 66 mph. I'm running a 216, so it's very happy operating at that rpm cruising easily at highway speed. With the 3 speed and 4.11, it liked to go 58 mph at 2,800 rpm- just kinda settled in there. With the T5, 2,800 rpm is 80 mph, and it will do it. I don't think it will do much more, but it has held 80 for a 10 minute stretch.
First gear goes away pretty quick. It doesn't like launching from a stop in second gear, but in stop and go traffic or coming up on a light that's just turned green, if it's still rolling even the slightest bit it's fine taking off in second.
My pumpkin was from a 55-59. Solid spring perches came from Classic Parts, pivoting perches were cut off and the new ones welded on. USA Standard Gear rear overhaul kit "ZK GM55CHEVY" came from Amazon, I think. Price shop it- lots of folks sell it. Once the rear was in and it was back on the ground, we measured for the driveshaft length and I had a local shop fab one. Used a stick from an SM420 four speed welded to the T5 shifter mechanism, topped with a custom shift knob.
I can't remember what T5 mine is- it's from an S10 and had the electronic speedometer output. I used a tail housing for a mechanical speedometer off an earlier T5 with a broken case. I had it rebuilt and the shop put a 10-spline Jeep input shaft in it. I use a stock 1950 3100 clutch package, and took less than 1/2" off the pilot tip of the input shaft. I did not use a crossmember under the rear of the T5.
The Art Deco trucks have a different trans-to-bellhousing bolt pattern than the Advance Design and later, and there is not a T5 that will bolt directly to that bellhousing without an adapter. That opens up the possibility of using later S10 T5s that have the Ford-style bolt pattern since you need an adapter anyway. I do not know first hand how the adapter thickness will affect the input shaft length (whether any should be cut off or not), but since I took so little off mine, I wonder if the Jeep input shaft can be used or not. Maybe Jay (Lugnutz) has some input (no pun intended) on that.
