We had a 337 and I flew it quite often on charter.
I don't remember any FBO's in our area using a 336 or a 337 for multi-engine
training. You could fly these airplanes with a checkout and your regular
multi-engine rating or you could qualify simply in the airplane itself with
a center-thrust rating that the FAA created just for the 336/337 series.
It was extremely stable and easy to fly and had none of the critical engine
aspects of a regular twin.
Dudley Henriques

"Robert M. Gary" wrote in message
oups.com...
It made a poor multi trainer for FBOs because the FAA would not issue
"full" multiengine ratings to students who took their checkrides in it.

-Robert