I could not find any result when I tried to search, so if this is covered somewhere I apologize. My 1988 W100 has been sitting so long now, that basically it is like starting a new project. One which means I will be replacing the cab first thing. But I have been thinking about swapping in a 4bt for some time. I know they are expensive, and that the trans and tcase will also have to go. But before I seriously start planning, I would like to hear some opinions from people who know more about it than I do. I am really thinking that a 4bt/nv4500/241hd combo would be awesome. Assuming of course that I can find the proper amounts of money lol.

 

ive done a couple 4bt conversions, they are only real good if you dont have the room for a 6bt, the 4bt will normally cost a bit more than the 6bt and they dont have the power, and they are rattly little motors, but cool none the less, with a 6bt and a set of first gen cummins motor mounts you can bolt the engine into your frame, then the trans and t-case is up too you, just remember the 241 has the opposite front output, so you will need a second gen front axle or something similar as well

 

I wasnt aware of the issue with the tcase, but now that I think about it, that makes sense. I would like to do this with as many "factory" parts as possible. Assuming I ever have the money lol. Is there a transfer case that will work without modifications? And is it true that 6bt motor mounts will fit a 4bt? I am pretty stuck on the idea of a 4bt and manual trans. Maybe there are other options, but its just what I want out of my truck.

 

the trans and t-case from an 98-93 cummins truck will be pretty much a bolt for yours, the 6bt mounts on a 4bt is a no-go, they will NOT work, custom mounts will be required

 

I dont think I would have a problem building a set of motor mounts. But I really want to stay with the nv4500, even if this is still the dream stage. Is there an adapter to mount my np231 to the nv4500? I dont plan on adding a bunch of power to the motor, and I bet I could make the 231 live a while. At least until I could get the truck finished and put some miles on it.

 

Upon further review, my truck has the 241. Not sure where I got the idea it was a 231. I would imagine that would bolt up fairly easily to a nv4500.