I don't think you will find a 4.5 inch back space, or a 4.25", which is what I looked for when I bought a pair for my 69 Z.
I ended up buying 5" back space, and use a 3/8 spacer to keep it from rubbing.
I bought mine new. But I don't think they make the 5" back space any longer.
There is a used pair on ebay.
https://www.ebay.com/itm/38436818256...kAAOSw66RhMNVe
And despite no one making a hub centric ring for them, you will want to run rings. You can have them made.