[b454rat]

I don't even know where to start lol. First, the engines you mentioned are entirely too heavy to put in a 1 ton truck. Second, they won't make the power of the Duramax. Third, noisy as hell. Fourth, prolly won't get the fuel economy as max either. Fifth, I dunno if they would even fit under the hood or between the fenders without some serious work.

You need a Dana 60 from a 86 to 92 Ford. They have the wider spring perch width, so be stable. They are cheaper and easier to find than the 78/79 style. The Dana 70 from a Kodiak is stupid wide, and don't know what the perch width is. It also has 10 lugs, so would have to change the rear out to match.

it sounds like you need a heavier truck than a 1 ton. They are a ***** to find, but a 3500HD, 15k GVW or something like that. But a 4wd is beyond hens teeth to find and not as easy to convert to 4wd.