Heh heh... 2-3 percent will be a measurable loss on what I'm doing. I'm aiming somewhere in the 1000HP/1000TQ at the crank. There's this 2013 Camaro I need to beat at the drags.

I wish I were going with a stick on this but my knee, which was cut on a few years ago, just isn't up to it anymore. But, given a choice between another scalpel and a slush box...

 

You're going to lose alot more at the trans than you will in the back.

Figure 10-15% loss in the trans takes 1000 in and puts out 850-900 to the driveshaft (minus 100-150). Lose 7% in the rear gear, you have 790-837 to the axle shafts (minus 60-65), lose another percent in the wheel bearings, 780-830 to the tires (minus 7-10).

And alot of the trans efficiently relates to how the converter is tuned to the engine.

I still don't think it's work hassling over 2% in the rear gear. 7-17 HP is easily made up elsewhere.

Also, if you plan to make over 700, don't go 12 bolt. The axle shafts are terribly week. Constantly hearing parts calls for them at the NHRA races. There's several people that keep 2 or 3 sets of spare 12 bolt axles for 2nd and 3rd gen stock eliminator camaros.