White-Hercules DT3.7 Series I. I'm in the process of installing one in a '68 CJ5. I picked up two of them complete from fan to transmission(T19) for about 2/3 the cost of the cheapest 4BT I could find. They're cheap. Supposedly ~125 lb lighter than 4BT. The ones I have were in early '80s Ford stepvans, labeled Ford Power Products on the rocker cover but with the White ID plate on the passenger side of the block. They have an adapter on the back that adapts the engine to small-block Ford bellhousing pattern.
The series I makes similar power to the Cummins 4B even though they are turbo. Nice thing is they'll deal with altitude better due to the turbo, obviously. They don't take too much to upping the power due to lack of a few critical changes between series I and II. Series II has factory power ratings on par with 4BT but also have asking prices on par with 4BT.
I don't know where the DJ lies in the dimension areas.
The W-H will just fit between the firewall and the front cross-member of the pre-'71 CJ5. I did clearance my firewall because I had some other things running back there but it's not a requirement. The postal grill should give plenty of room for a radiator. I used a '74 grill and a generic aluminum radiator to move the radiator forward enough to use an engine driven fan. I kept the close ratio T19 that came with the engine and this one is 2x4 for now, just like a DJ...
Ken