Anybody know anything about these? A buddy of mine and I have been hunting for a Dana 60 for his Blazer and heard about a '74 dually that is, supposedly, a 1-ton 4x4. From what I saw in the brochure and what we heard from a local, long-time GM parts guy GM didn't make 1-ton 4x4 trucks in the early '70s. Is this true? We were told that there were a couple of companies that did aftermarket conversions; I'm not exactly sure from what to what. Maybe a 3/4-ton 4x4 to 1-ton 4x4? Or 1-ton 4x2 to 1-ton 4x4? Anybody familiar with this? I'm kinda curious. I know GM didn't start the Dana 60 in their 1-ton trucks until '79 so what would an aftermarket company have used?