I just thought I'd stir up the "how much power do you really need?" debate. My first diesel truck was a 1959 Mercedes 319d, possibly the first factory diesel pickup in North America. It was a 1-ton dually, powered by a Mercedes om636 diesel. This was the same engine used in the 180d cars, the 401 and 411 Unimogs, Thermo-King reefers and bunch of other industrial applications. It developed all of 40 hp from 1.8 litres. Top speed was abou 45 mph, not all that different from the original Jeeps. I got used to it and it seemed adequate everywhere but on freeways.
My second was a '77 Ford half-ton powered by a Nissan 3.3L. It was the industrial version, rated at 83 hp, and it wasn't adequate. It would cruise at 60 mph under perfect conditions, but I was down to third gear for headwinds or slopes that I wouldn't have noticed even in the Mercedes. Since I had to run at full throttle most of the time, it also smoked like Mt St Helens.
Since then, I've been driving Dodge/Cummins diesels. No complaints about them.
I haven't entirely abandoned conversions, though. My '78 Winnibago has a Perkins 6-354 turbo in place of the original Dodge 440. Even with 100 or so less hp than the original ,it doesn't bother me.
I have another 6-354 that's in the process of going into a GMC DUKW, and if I ever find the time, I'd like to put a diesel in one of my M-38 Jeeps. I haven't decided what to use. I have several of the Mercedes om636's: car, truck, Unimog and reefer versions. I also have a few Mazda 2.2L pickup engines. I don't have any spare Kubotas, although my Bobcat and welder are Kubota powered. There is, however, a shop not too far away that puts Kubotas in Jeeps so it's kind of tempting to do something that someone else has already worked the bugs out of. I also have a CJ-2 that someone started to put a VW Tdi in. I'm afraid that when I get a closer look at it, I'll find there were good reasons he gave up.
