Well in fact torque is what is actually measured by any rolling road. Power is calculated from the raw torque figures. As Matty says, the only value in a rolling road run is in comparing a batch of similar cars with different mods, eg on a club shootout day. Getting an absolute figure is a shot in the dark, all rollers vary, even the same rollers can vary from one week to the next. THe most accurate I have found are at BB Tuning and give roughly what you would expect if youre being conservative in your estimates.
Best way to really know how fast your motor is is to start quarter miling. Once you can be reasonably consistent with a bit of practice youll soon see the difference between a healthy Willy and one thats down on power - a standard good un or one with a few basic induction/chip/exhaust mods will run 15 seconds or less. A tired or slightly underpowered Willy will make a 15-16 second pass. Any slower than 16 seconds and youve got big problems.
