stock 3.07 gears - how low can I go?

[GMC-YA68]

My truck has factory 3.07s. Factory D44/12B. With my LS swap which consists of the overdrive tranny, the overdrive gear and my tire combo will be basically worthless unless I plan on cruising at about 90mph! How low of gears can I swap to with these axle housings? I'd like to end up with 4:10/4:11 --whatever. I have read about series 3 and series 4 carriers but having a hard time understanding what is actually what.

My truck is a 72, non-posi rear end.