Qtr mile or ENGINE dyno results
You'll notice it talks about " HP st the crank" as one of the co-efficients.
When you think about it - it stands to reason - how could a formula possibly take drivetrain losees into account? They are different for evety car - and theres no provision to vary them in the formula or on the slide rule.
The sad thing is that even people at Moroso think its rear wheel - but then they dont understand how it all came about.....those guys died years ago.....