So it looks like I was close with my 75 HP estimate with this test?

 

Your mechanic buddy is wrong, unless the laws have changed recently.

 

We don't have these inspections; how do they do that test with a manual trans?

 

Here's the history of it from Wikipedia for reference...

Emergency brake

The emergency brake was originally intended for one particular emergency and that was "no way to stop", as was the case when the footbrake suddenly failed. Drivers had to respond when brakes failed, so they were expected to learn how to stop a speeding vehicle using the emergency brake alone. Safety regulations became almost universal by 1980, so modern brake systems are very reliable, using dual-circuit hydraulics and more recently low-brake-fluid sensors. As modern brakes no longer cause emergencies (a brake warning light comes on after the first sign of trouble), it is no longer necessary for the average driver to learn to use this brake for emergencies. Some drivers benefiting from the "park" function on their automatic transmissions do not this brake at all(daily use of the park brake is recommended). After a lack of recent history with braking emergencies, automakers stopped using the term and started calling it by it's other use, the "parking brake" even though the ability to function at a high speed was still there. On an increasing number of modern vehicles, the park brake can only be engaged when the vehicle is at a stop, they no longer have an emergency brake.

 

I think this applies to automatic trans (at-least in my case it does), but if I could guess at how the test would be performed for a manual trans, then I imagine they would use first gear from a stand-still and ride the clutch to affect some forward thrust just short of causing the engine to buck & stall, else they might use the hand-brake to stop the car within a specific distance (like ~80 ft.) from a specific speed (~20 mph).