1968 C20 to C10 frame differences?

[KevinK7]

Will existing C20 parts bolt right up to a C10 frame?

I'm relatively new and did a number of searches, yet still not 100% sure on the differences of the actual frames themselves. (If there are other threads on this, please post links)
I know a C10 is a 1/2 ton and C20 is 3/4 ton, I know there are differences with the rear axles, lower control arms, etc. However with the actual frame itself, what's different?

I have a '68 C20 longbed (396 4sp) that I plan to lower a bit and go to shortbed. (also going to 5/6 lug, disc brakes, etc.)
I could cut/shorten my existing C20 frame, but I have access to a 68 C10 shortbed frame only. I'm going to disassemble the truck either way but I'm hesitant to cut a perfectly good frame, will the '68 frame work?

I've looked at Early Classic's spindle kits (that work with C20 control arms) which I will most likely go with. Then in the rear, I realize I will have to change out the rear/axles (going to 5 or 6 lug).

So, ...Will the existing C20 parts bolt right up to a C10 frame? and/or is there any reason to just go for all C10 parts?

Thanks in advance for any information,

Kevin