Originally Posted by skytop
The 3.92 is a poor choice for fuel economy unless you enjoy forking over your cash big time at every fill up.
Not necessarily true, it all depends on your terrain. I had the 3.92 gears in my 09 QC Hemi and always got better MPGs than my friends with the 3.55's. The reason being, the motor did not lug down as much. 8spd, 5 spd, doesn't matter as the top OD gear is the same. Lots of threads on this. If you have any hills at all, the 3.92's are the way to go.
As an example at 55 mph, your RPMs are only about 1,300 in 8th gear with the 3.55's and 33" tires.