Longbox55, I cannot confirm the 3.90 3/4 ton set from the original run. I only know what I've been told, and I know that Art Hauser reproduced them for a short time before he was killed. I found a couple posts that reference that set as originally being a 1970 only offering, which makes my earlier recollection of 68 void.
As far as 4.10 vs. 4.11, that's semantics at this point. The math comes out the same basically. That's like when someone tells me that my truck isn't a 4.57, but a 4.56, even though 4.57 is stamped right on the data plate. You'll find that all of the early documentation of trucks equipped with eaton rear ends, shop manuals etc. regarding half ton trucks will state that they had 4.11 rear ends up through 53. Eaton rear ends in half tons from 54 and up are referred to as being 3.90, and Spicer rear ends are referenced as being 3.92. That didn't stop them from putting a Spicer rear end with an Eaton front end on NAPCO trucks starting in 57 for GMC.
