Earl, there is only torque being measured on a dyno (I assume you are asking with respect to dyno numbers). The hp is calculated from the measured torque. Therefore, if you assume a simple percent loss for the torque due to the drive train then this loss would also apply to hp.
HP = Torque * RPM / 5252
Torque is measured in foot-pounds for this equation to be correct.
Ron
HP through the usable RPM range is what matters.