I posted the results from Hotrod in another thread where they ran the Hellcat, Camaro and Mustang on Kenne Bell's dyno:
http://www.hotrod.com/cars/featured/1504-2015-dodge-challenger-hellcat-dyno-test/
Originally Posted By: Hotrod
Strapped to the dyno, the eight-speed automatic-equipped '15 SRT Hellcat Challenger from Chrysler's West Coast media fleet produced a corrected rear-wheel peak of 620 hp, happening at the fuel-limited 6,200-rpm redline in Fourth gear. (Rear-wheel torque maxed at 579 lb-ft at 4,200 rpm.) By comparison, a stock '13 Chevy Camaro ZL1 six-speed automatic maxed out at 465 hp at 6,300 rpm (also run in Fourth gear and limited electronically by fuel), and 473 lb-ft of twist at 3,700 rpm. The completely stock '13 Ford Mustang Shelby GT 500 was a six-speed manual trans model, and in Fourth gear, put out peaks of 587 hp at 6,400 rpm and 575 lb-ft at 4,300 rpm.
If we use the 15% driveline loss figure:
1. Hellcat, 620RWHP = ~713HP (707HP rated)
2. Camaro, 465RWHP = ~535HP (580HP rated)
3. Mustang, 587RWHP = ~675HP (662HP rated)
It would appear the Hellcat and Mustang are overachievers.