Denny, my name is Josh.
If you follow this link, and go to page 83 of the .pdf, which is page 13 of the axles and suspension section, you will clearly see the cross section of a HO-52 or HO-72 center section. You will furthermore see the gear ratio of 4.11, and 37/9 tooth count, optional on C, P, and K 20 series trucks. This is dated August 1st of 1965, for 1966 trucks.
https://www.gmheritagecenter.com/do...hevrolet-Trucks/1966-Chevrolet-Truck.pdfThe same diagram can be see on on page 87 of this pdf, or page 20 of axles and suspensions for 1967
https://www.gmheritagecenter.com/do...hevrolet-Trucks/1967-Chevrolet-Truck.pdfI won't speak further about the 3.90's other than I recall when Art was selling them and I was too poor to buy them, and I know at least one guy that did buy them, and I've known him for over 15 years. His name is Sam Hagopian and he's no liar.
You asked for documentation. There it is.
Apparently for whatever reason, Eaton changed configuration at some point from 37/9 to 41/10 and therefore changed the ratio.
They changed the format of the documents in 68, 69, 70 etc. My assumption is that the ratio of 4.10 refers to the new 41/10 HO 52
If you continue to argue this point,you're arguing with GM, not me.
