4x4 conversion

I have a 79 1ton dually and I want to convert it to 4x4. Will swapping the frame with a 1/2 ton 4x4 frame work?

Yes but you can't do 1 ton dually stuff anymore.

Anything is possible. Rear aXLe won't bolt up without some work. I say do it! Don't forget to keep a build thread on here with lots of pics.

The ton frame is definitely different than a 1/2 or 3/4...unless it's a Crew. I too have a '79 dually that I'm going to convert. I was able to source all the components from a single cab K30 that I bought for parts. I cut the frame just behind the rear spring mount on the front so that I'd have whatever when the time comes. The 2wd rear spring hangers will have to be replaced in all four corners and replaced with 4wd; unless you want to run lift blocks. You can use all the 4wd spring hangers from a donor truck on the front but be advised that the front hanger is also the radiator support mount. I don't think there is any difference between the 4wd frames from the front cab mount forward so finding the front crossmember and mounts should be easier than finding the rear.