I had always assumed this 14 bolt FF rear under a '74 Crew cab 2wd I had was 3.73's. Then I pulled the cover, and I saw the number 41 and 10 stamped on the ring gear. Cool, it's 4.10s, and I need a 4.10 1-ton rear for this other truck. I pulled the old rear out, and went to put the 4.10 14 bolt in. "I wonder what date reads on the ring gear" I wonder. I glance one last time before I bolt the cover on, seal it and install it and finally would be done with this truck. 73 for the year... hmmm... and a 10 for the pinion tooth count... no wait... that 10 is a month. October of '73. Ok. Wait... if the 10 is part of the date code... what's this over here before the stamped 41. AWWWWWW CRAP!!!! It's an 11... it IS a 3.73. 11 and a 41... spaced apart further than usual. Now I'm screwed on my "quick axle swapover". The moral of the story... make sure you know what numbers your looking at before making life changing decisions for your axles. My glance was deceiving.