Hi Vandy,
Well, this is exactly what I'm doing to my bronco! I have a 4bt with an NV4500 behind it. I'm in the process of welding in the motor mounts which there appears to be a million different ways to do this. I bought the nv4500 crossmember from wild horses and bolted everything up. I'm burning in the motor mounts where they lay after the tranny is bolted in.
There are a number of different opinions about which tranny to use with this motor. The cummins motor has a lot of vibration. The diesel NV4500 was designed to handle this. It has a very low first gear and a high 5 gear which makes it ideal for the short powerband of the 4bt.
I found a guy on craigslist that was parting out a '99 Dodge 3500 4x4. I got everything off of the truck I could. At a minimum, you will need the adapter plate off of the back of the cummins to mount the tranny to your 4bt. But, I also got the pedal assy, the hydroboost, clutch master cylinder, etc.
The great thing about the 4bt is that all the parts off of a 12v up to 1998 dodge cummins will bolt up and some off of the 24v.
As far as the transfer case, you can buy an adapter to bolt up your dana 20 if you want, but I wanted to have the modern convenience of shift-on-the-fly. So, I grabbed a transfer case off of a dodge cummins. Now, keep this in mind if you go this way. New Process put 2 different cases in the the later model dodge diesels, an NP241DLD and an NP241DHD (this is noted on the mfg tag on the back of the case). Also, the input spline count is different between and automatic and the NV4500, 23 vs. 29 splines, but this can be swapped out for a little over a $100. You will also need to put a slip yoke eliminator kit on it. Now, there is not a sye kit made for the DHD case, so you will have to find a DLD case! You can get the sye at jbcoversions.com.
You will need at minimum a 2" body lift and a 3.5" suspension lift. You will also have to clearance the oil pan to clear the differential, and of course, modify your transmission tunnel.
There is a lot of work to do this, but in the end, it's an awesome conversion!!!!!!!!!
Here are a few builds:
http://classicbroncos.com/forums/showthread.php?t=174452
http://classicbroncos.com/forums/showthread.php?t=209588
http://classicbroncos.com/forums/showthread.php?t=102385
Also, you can gather a ton of info on the 4bt at:
http://www.4btswaps.com/forum/forum.php
A word of advice... Make sure you read the stickies, study them, memorize them, before asking a question. They don't like to just simply help someone by answering a simple question.
Good luck!
Let me know if I can help!
Andy
