anyone know, is it possible to put a 3.08 gear in a 2.73, 2 series? i know anything lower will absolutely not work but i heard the 3.08 might.

Nope, will not work. 3 series- 3.08 & up, 2 series- 2.73 & down

The 2.73 is as far as you can go on a 2 series in the 12 bolt and 8.2 10 bolt. This is not true in other rear ends.

You can put a 3.08 gear on a 2 series carrier with a ring gear spacer, But you may have problems with the ring gear bolts breaking or backing out.

I know there's a spacer to put a 4 series gear on a 3 series carrier (would be .305" thick),but not too sure of a 3 series gear to a 2 series carrier (would be .430" thick).
BTW ,I'm not a fan of spacers.

Yes, you can use this spacer. You can make up the difference with the differential shims. I never recommend using a spacer, but sometimes you gota do what you gota do.

what size of spacer would i need to do this? thanks