[olddog]

One of the biggest variables in measuring Hp is the fact that they correct the measured Hp to what the engine would have produced at sea level, at a given temperature, and a given barametric pressure. This is done to standardize the result so that no matter where the test is done everyone would get the same result. The problem is the formulas to correct for this have been changed numerous times, and they know that the formulas are still not exact. Then you have errors in the measurements. And most importantly how honest is the man doing the correction. One dyno expert told me that if he wanted to he could move the numbers a bunch, and still claim it was done correctly.