Excellent mod/job. Craftsmanship at it's best!
I tried to change out a pull-mor in my Lionel "War-Horse" a few years ago. Was going to replace it with a can motor (Timko). Total disaster!!! I was trying to use the original boards by modify them to accept DC. There was an article by a fellow that did that type of mod on American Flyer engines.
Ended up selling the can motor. Reinstalled the pull-mor and sold the engine (or should I say...gave it away).
Your mod should be a resounding success!