I saw a very original and nice 1.5 ton AD on ebay last year, it was in Montana. Very burly conversion and it appeared to have been that way for a long time, most likely upfitted when new

Sounds like Napco was making big bolt components at some point and I've also read that Marmon Herrington (usually associated with Ford) was also making components and conversions for GM trucks.

I've never seen a Marmon Herrington conversion on a GM truck, especially a big bolt. Did they ever exist?

I have a chance to get a deal on Ford MH 4wd components and am interested in swapping them into a bigbolt AD....If it was an original possibility on a Chevy I'd be a lot more motivated to start the project.

What says the Stovebolt braintrust?