can someone clear up my perception that the M36 are based on the M10A1 chassis and that the current academy offering of the M36 has the wrong engine deck or do they work both ways?

The M36 was based on the M10A1 (which had the Ford GAA engine (like the M4A3)). The M10 shared the same engine as the M4A2, with twin GM Diesel engines.

The Academy engine deck is correct. The new AFV Club engine deck is incorrect. They screwed this up just like their M35 tractor.

Inexcusable by any stretch of the imagination.

And to be accurate, no M36s utilized the M10 (GM Diesel) hull. You'll need to modify the kit or get the Academy one.