On the window sticker of my R/T 6 speed with 20's it list the rear - end ratio as 3.92 . But in the Challenger brochure it list it as 3.91 for 20's. In many of the post some say 3.91 and some 3.92 . Can't be two ratio's . Or am I wrong .

 

My sticker says 3.92s also - but I've also heard 375 and 376 hp with the 5.7 6-speed... who really knows. Doubt 1 hp or a .01 difference in the rear end ratio really makes that much of a difference...

 

3.92 from all I have read. They are just reliving the past with the 3.91.