[RWebb]

you are right

I've driven other vehicles several miles that way w/o damaging the alternator, but no warranty on your 911, or particular model of alt. & voltage regulator.

I'm also just guessing that the tach. contains all the solid state devices for the pulse counting and that none are back in the engine compartment. If true, no damage. If not true...

You can certainly run a motor on a dyno w/o all the accessories, but that doesn't sound like what you are up to.

Worst case, check the schematics for everything on the 14 pin plug and then pull some pins if you need to.