Originally Posted by PWR_SHIFT
Actually it's pretty simple (and stupid)-
The advertising genius that put the '05 brochure together got the LS2 HP & Torque numbers from GM Powertrain folks and just assumed that the engine speed at the particular peaks remained the same as on the '04 LS1 (take a look and you'll see that the advertised rpm is just like for the '04), while in reality the rpms should be just like on the '05 Vette (6000 and 4400, I believe). That's why they needed to increase the max rpm from 6000 to 6500, so that you woudn't drop below the torque peak point after a shift.
Aha, just as I thought!
Actually, what I based my observation on was this:
To get a rough idea of the peak horsepower, use the formula HP = torque (peak) x (rpm-torque + rpm-hp) / 10504.
In other words, add the two rpm speeds, multiply this sum by the peak torque and divide by 10504 (twice 5252). This gives you a rough estimate of what to expect for peak horsepower.
(Note: If you you use this formula enough, you'll find that it does fail at times.)
So trying this on the 6.0 liter engine with the correct
6000 + 4400 = 10400
400 *10400 / 10504 = 396 hp.