60-66 K20 rear drum brake info needed

[Short 3/4]

I am looking for any pictures/information/parts sources for the 12x2” rear drums on a K20

While there is much information on the 1/2 ton 4x4’s and 2wd 3/4 tons, unfortunately the 12x2” drums on the K20 are a completely different animal. While some vendors mistakenly show crossover of some parts, there is NO crossover between K20’s (front or rear) with any other truck models (other than rear hub bearings, which are the same as a 3/4 ton 2wd).

My main questions are:

When did Chevy switch from slip fit to press on drums in the rear? I’ve seen slip on drums on a 64 and press on style on a 66, but can’t find any definite info on when this changed.

Did the drum stay the same and the hub was different between the two styles, or was the drum also different? LMC shows the same drum from 60-66, but they are not always a reliable source of information.

Are the rear brakes the same on a Chevy Eaton style rear as on a GMC Dana style?

Did the rear brakes stay the same on the 67-72 K20’s?

Any information and especially pictures of what you have would be great. I know there are others out there with some of the same questions.

Thanks,
Tom