Upgrade a 1/2 ton 63-66 to a 3/4 or 1 ton?

[inquirer]

Hi, first I'd like to say that I've been an unregistered lurker for several months & greatly appreciate all of the quality info that is posted here..

So, I'm in the market for a long bed 3/4 ton or maybe even a 1 ton pickup for some various occasional heavier-than-1/2-ton personal use & I would love to make a 63-66 Chevy work for me, but I'm finding a lot more reasonably priced + nice 1/2 tons than 3/4 or 1 tons, especially in 4x4's, which I would prefer tho it's not necessarily a must.

Is the difference all in springs & axles, etc. or are the frames more massive also? And one of the threads for the newer trucks mentioned the cab fasteners were also heavier duty than the 1/2 tons? Does anyone know the complete scope of the difference between 1/2 ton & 3/4 ton & 1-tons for the 63-66's???

Thanks!