i don't know where chrysler get's it's horsepower numbers, but if you take a look at the dyno-charts on the hypertech, or superchips website, they show the horsepower is under 300 (279 to be precise) even after performance tuning it's only 287. that's a long way from 345.

the hemi is also supposed to produce 350 ft lbs of torque, but the charts show it to be 300 ft lbs.

check it out for yourselves.
hypertech dyno

has anyone put theirs on a dyno?

 

There is a difference between rear wheel and engine horsepower. There is an efficiency to calculate in when the power is distributed through the tranny, t-case, gears... to get to the rear wheels. All manufacturers advertise the engine horsepower.

 

He's right, their claim is engine horsepower, not wheel horse power.

I've heard the the drive train loss is roughly 23 percent.

345 HP x 23% = 79.3
345 - 79.3 = 265 hp

 

Also, to compare RWP effectively, all vehicles need to be tested on THE SAME DYNO, CONSECUTIVELY. THis will eliminate differences in barometric pressure, temp, etc. Different dynos will give you different numbers. Dyno A will show different than Dyno B.

While auto trannies have become more efficient, they are not 100% efficient, nothing is. Some are more efficient than others.

Manufacturers advertise flywheel HP. In the old days nothing was attached. No PS pumps, no alternators, etc. That is why the numbers where even higher. Now you will see SAE adjusted HP which tries to make an even playing field.