[Richard]

A scan of the back cover of a 72 Chevy truck brochure I have in hand. Hope it is readable. Odd that it lists 3.73 as standard on the K10. Mine has 3.73 listed on spid as added, can be seen in post. More confusion for me. See it now- note at bottom. 3.07 ratio used with all 350 engines. So, once 350 is added as option 3.07 is standard and 3.73 is option.
Another add- Yukon gear has a 3.54 ratio and 3.08 for the D44 front as well as others. Expecting some to not agree with me on this, the 3.54 is acceptable to use with a 3.42 rear in off road use.
Realistically, probably less than 100 rpm difference between the 3.08 and 3.73 final drive. So why go with odd gears.