with all this talk about different HP numbers at the wheels and the crank, how does one go about measuring the crank HP? do you have to remove the engine, sit it on a table and strap it to a dyno? excuse my ignorance.

Unless you know the exact driveline loss (!), you generally have to pull the motor. This is why chassis dynos are more common. The only folks that have a bench dyno are generally those who build / rebuild engines from scratch. Mostly "hot rodders"...think domestic V8's and such. There are two basic types of bench dynos...steady-state, and inertial. Steady-states are fairly simple... the motor is connected to a generator and it is run up and down the RPM range to see how much power it generates...1 HP = (about) 745 Watts. Inertial ones are much more fancy. They have a large flywheel that the motor attempts to spin up. This gives a more "real-world" load than a simple electric motor can.