82 GS850 parts bike for 79 GS750

[Northern Mike]

I have an opertunity to pickup an 82 gs850 RUNNING, as a parts bike for my daily rider GS750. Coming into winter and rebuild season, I'm thinking of jumping on the gs850 for parts for my daily.
What parts are worth moving over and what won't or shouldn't be brought over?
Looking at the jugs, pistons, coils right now.

[azr]

A lot of the parts from the 82 850 won't fit the 79 750, completely different bikes really.

[tkent02]

Cylinders and pistons fit.

[Northern Mike]

I'm looking at a few mechanical pieces like the cylinders and pistons, but also the coils, turn signals, rear tail, maybe headers if they fit as my chrome is rough, etc. My seat pan is also in rough shape with the hing mounting points flexing due to rust.
The gs750 was a partial restore after sitting for a year or two. Runs but needs a few things.