The first year of the 6.5 had a mechanical injection pump and would make the best of both worlds, no computer/no opacity censor. You can use diesel to waste motor oil for fuel just like the 6.2. But if you can get a surplus military 6.2, it has more metal than the civilian model. The easy part on the tranny would be put a built 700R4 behind it, again no electronics. And lots of transfer case options.

