I got my 273 Tcase from TOby Lavender at Triple X traction. It was 1200.00.
-It comes with an adapter/clocking ring to mate to the allison.
-The input shaft is changed to except the allison output.
-The case is tapped to except the GM 4x4 electric motor that switches the Tcase
-It will also come with the vehicle speed sensor in it to plug into your factory wirring
- The 273 case is really big so it moves the front output closer to the frame which allows the HUGE 1410 cardan joint front driveshaft to fit without hit the alli
High Angles front shaft is huge compared to a normal Dodge or Ford 1 ton front drive shaft.
By going this route it does a number of good things since we have switched to a live axle instead of the IFS. Gives you a fixed flange on both outputs of the T-case. This way the drive shaft has the slip in it the way it should for a live axle front and rear.
I went with High ANgle Drive line front shaft was $1,000.00. I have enough lift I needed the cardan at the Tcase gives me up to 42* of working angle it sits at about 20* total working angle at ride height. In the rear I am going to a 2 piece steel drive shaft with a pillow block carrier bearing setup instead of the 1 piece alum. Again the driveshaft will have the slip instead of the T-case.
I have about 12" lift will be running 40"s but this really should pertain to your build as well. From what Toby at Triple X and Jess at High Angle have said this is by far the strongest way to go. I plan to do Tug-A-Truck on concrete and go to Silver Lake Sand dunes so I don't want my driveline to be the weak link.