I know this is ass-backwards, but I have never actually confirmed what I have for rear end gears yet. Build sheet says 3.08, but based on rpm/mph, it feels like one of the 2 previous owners may have swapped in 3.42 or 3.73 gears. Neither previous owner says so, but it pulls pretty damn good for 3.08. However, first gear feels pretty tall with the tko compared to the ST10, so I'm thinking I may still have 3.08. I have to pull it apart anyways now that it is on stands for other work including a posi, so that will tell the tale. If it is still 3.08, I will install 3.73 gears which I'm sure will suit my needs perfectly. I like the idea of 4.10, but worried about making first gear useless. I also like to run at high speed on the highway, and 4.10 will only increase driveshaft speed which I'm leery of.