Duramax max all the way. I have 130k on mine never a had a failure on it before mods or after. mods have been on sense 80,000 miles tranny went in at 115,000 no problems what so ever. had a buddy with a 6.4 all stock injectors went out at 30k miles, then they gave him a new one, and started blowin coolent lines. IMO id go with the duramax or if you could actually find a good 5.9 cummins

 

Before I bought my 05 dmax I looked at numerous fords.I loved the way they looked and everything about them but I had heard to many stories of horror about these things having problems and especially problems that I couldn't afford to fix if they occured just my. 02.

 

dont get an lb7, my neighbor has 130 on his and injectors are toast.
I said it before, I'd go 12v cummins or 7.3 powerstroke for a work truck.

How about the old gm mech. diesels? I heard they were good on fuel. I don't know anything about them.

 

Id go with a 6.9 or 7.3 Ford before I would the 6.2/6.5. They're all gutless though

 

agreed with easter the 6.2 and the 6.5 mech inj engines are very reliable but they are not work horses within my family we have owned 2 6.5s and 2 6.2s the only one we have left is a military blazer that sits on full ton axles with military 38s we use it for rock crawling and its awesome my issue with the cummins is people want double the value of and dodge truck with a cummins thats why i never bought one i refuse to pay 10k for something that only books for 5k or 6k