New here, 68 with some questions

[wpsharpshooter]

Been lurking a while. My dad bought this truck back in the 90's. So it looks like it was redone in the 90's. He wants to bring it in to this decade now so Im trying to get some ideas for the truck. He is wanting to dump some money in it when the weather starts to warm up. We have a guy that works on these old C-10s for a living and hes offered up some suggestions.. We are looking at lowering it, putting discs up front, and switching over to 5 lugs. Im curious as to what companies you guys are using for these items. Also curious what kind of wheels sizes we should be looking at, backspacing and all that. Wanting to run 20's, with maybe wider wheels in the back. Not really sure yet. Just kinda piecing all the things together now.. Best pics I have currently