c20 Hub Size help!

[Mr Handy]

Hi, A buddy of mine is working on his 70 C20. He is converting it to a dually. He has a set of dually rims that are hub centric and the bore measures 121.3mm
perfect for the front dually spacers we found at the swop meat off a dodge.
I measured the hub on the c20 to be 4.605" or roughly 117mm.
can anyone conform the stock hub size on the 70 c20 and also point me in a direction of a good place to find hub rings for the application. We definitely want alloy rings, not the plastic ones.


Thanks in advance.
here is a pic of my 10 and the 20 in question, the only pic of the c20 I could find.