What is the size of the Jam nut I need for the front control arm?

Can anyone tell me where I can buy this nut? The spindle nut for the 9" brakes is unique...Mopar part# 2072731 and I also found out it is superseded to part # 6029691 I called local dodge parts dealership and they say both of those part numbers are no longer available. Discontinued. Parts stores are unable to cross reference it also. I did go on Oreillys auto parts website and found a few nuts but I dont have the dimensions to this nut. Is a dorman 9/16-18 hex net the same? They show several hex nuts on the their website but not sure which one it may be on Oreillys website

Wizard

Try a salvage yard?

I very well might have one if the stuff we removed from my son's 65 didn't get tossed. If I do, it's yours for the postage.