'71 GMC 1500 control arms

[FrankenCub]

I finally replaced the original shocks on my GMC today after about 4 hours and 10 sawsall blades but in the process notice one upper has started to rot out and the lower is really thin where the shock bolts on. In searching old posts it looks like newer control arms will actually work with using the '71 ball joints. Just how new years can I use and is there any benefit to using a much newer model year such as being stronger built ?
These will get me through this year safely but this winter she will be tore down to have all 4 replaced so over the summer I will gather the parts I need, used around here should be plentiful at our local u-pull-it.

One other thing while I'm here, the core support. Zero GMC core supports around here and mine is really bad but I read that the Chevy one can be converted. Is that just a matter of putting the GMC light buckets on the Chevy support ? I couldn't find any posts that actually went to any detail about it.