sandiegohemi said:All manufacturers list flywheel numbers only. So yes, the Hemi is putting out 345 hp and 375 ft/lbs of torque at the flywheel. The difference comes when it has to run through the driveline to the pavement.
Unfortunately, not all dynos are created equal, so you'll find numbers all over the place. And it depends if you are asking about 2wd's or 4wd's. If you do a search on here, you'll see 2wd's putting down 260-265 rwhp. A while back a guy with an 05 4x4 dyno'd his at 268 rwhp stock.
As you can see, there is no simple answer to your question. You have to take into account the type of dyno, temperature, humidity, accuracy of the machine, 2nd or 3rd gear pull, etc.