If I understand it correctly, dyno's measure horsepower and calculate torque. There is no way for a dyno to measure torque since what the tires put down against the road (or against the dyno) is force (in pounds) rather than torque, and that force is a product of the engine's torque, multiplied by all gear ratios, divided by the radius of the tire in feet. Since horsepower is lost in the drivetrain, the calculation of torque is going to be low because its based on the horsepower measured.

The conversion is HP = Torque * (RPM/5252)

 

That’s interesting; I always thought Dyno’s calculated the horsepower based on the foot lbs of thrust (torque) it was measuring and the RPM.

I thought I’d post up another Dyno sheet in case someone besides me finds it interesting. I found a Dyno on the KRC Performance site for a stock 2000 Durango RT 2wd and a 5.9L engine. After doing some research it seems chassis Dyno’s are not all the same. Results can vary from Dyno to Dyno they recommend it be used as tuning tool only with runs being done on the same Dyno and compared. I plotted the Durango’s Dyno results on my Dyno Sheet. The result, although not exact, shows pretty conclusively that the M1 and Cam that I’ve put in have resulted low RPM TQ and HP loss and high RPM gains. This is pretty much what everyone has said about these mods. It looks like I'd need not only headers but heads to get real good gains. I’d guess the heads are the critical piece.

 

Yeah, my guess is they were calculating torque with the wrong equations like gear ratio or tire size or something like that.