I don’t think the OP is interested in remapped engines or old engines that are no longer available. His choices are the 1 HZ or the V-8. I would take the single turbo version of the V8. He is looking for something reliable that he can use over long-distance traveling. At least I think so
First suggestion is to let us know specifically about the rear axle: make, model, ring gear diameter, axle shaft diameter and gear ratio. It is your vehicle, you should do the research. Or else contact a vendor that can profit from the research like forum supporter Nitro Gear.
1) LC axles might be too narrow
2) 70 series rear axles often have a 5000 lb (2250 kg) rear GAWR but front might be lower. What is the Dyna’s rear GAWR?
3) find out the Dyna’s ring gear and axle shaft diameters. The LC is 225mm and 33mm respectively. Downsizing is not a very good idea.
The 1138 has a great 0.732 high range, rpm in top gear even with stock 7.8s would be only 2000 at 60.
However the 3700SP is designed for a married TC and I believe the 1138 is divorced. Also its’ torque rating is only 6500 ft-lb. 6.93 x 860 x 2(for torque converter) = 12000
Try Neil Webster at merex.de parts dept in Germany. It has a 22mm shank and thread. Just out of curiosity what is the offset (“ET”) of your wheels? Mine are 90mm, which means my track is 142mm wider (1970mm), makes the tipping angle about 2.5 deg greater
Why would someone build a truck like that and use it for 1yr and 20Kkm and then announce “done with travel “?
Just a rhetorical question
It has all the right options - working gears, CTIS, EAS (automatic shifting of manual trans). Only drawbacks are tiny black water tank (19L) and...