The SS runs low 15's stock when new. I did a 15.3 with 950 miles on the odometer. You won't see to much dyno information on the SS because there is only one kind of dyno that I have found that can accommodate a full time AWD with such a large wheel base. It is an unusual dyno where you remove the wheels and bolt a dyno to each wheel (http://www.dynapackusa.com).

Using a ET Calculator, you can approximate the wheel HP. I know my SS weighs in at 5238 + driver = 5458. To get my 15.3 time, it takes about 300 wheel HP according to the calculator. Chevy claims the SS motor is making 345 at the flywheel, so this means I am only seeing a 13% drive train loss, which sounds way too low to me. I do think the 25% loss numbers for AWD that people suggest are way out of line. I guess I will find out for sure someday when I get to the dyno.