Spindle Replacement

Hello all. Discovered today that the spindles in my 71 Duster w/later model k-member, are no good. So I am on the hunt for replacements but I can't find anything. Everything found on the web supports disc brake conversions. Are these conversion spindles no different than the ones that come OEM on the later model k-members or are they not the same?
If they are not compatible what are the alternatives? I've read about using b and e body but it requires you to swap the upper control arms due to ball joint impingement issues and not wanting to go that route due to having just invested time and money in my upper and lower control arm restoration.

Thanks for any and all tips.
1971 Duster 360