Easiest, most popular engine to work on:

Series 60 by far. Cheap parts, just about anyone can work on them, reliable and there are a ton of them out there.

 

Mechanical engine? Probably the Big Cam.
Electronic? From what I honestly know, would be a N14 or a DD.

 

Can't help much there. I've been playing with an old A block 3406 but that's pretty much the extent of my knowledge on big displacement mechanical diesels.

 

3406B I was not impressed when a Series 60 started to freeze up and when I went to crack injectors there was going to be some wrenching just to get at the injectors...from then on "not my truck,, not my problem"

 

In the mechanical line I would say NTC 855 Cummins. They can be made to really thump and live.


Myself personally I have never been a fan of the small block Chevy. I am a big block man thru and thru. I feel the same about a 3406B CAT. True a Big Cam will take more heat, but you can make horses and fuel mileage without heat.

 

Without a doubt, the Big Cam Cummins. It powered everything from tugboats to farm machinery. It was the standard of the industry for many years. Not the easiest to work on, though, that would be the 2 cycle Detroit's.

 

I don't believe there are even injector lines on an S60. I seem to recall its a fuel passage inside the head. Its been about 7 years since I had its baby brother (a Series 50) apart though so I could be wrong.

 

You are right 60 series are common rail.