Yeah, I've actually got a B&M flexplate for a non-magnum 360. The part# comes out 727, but the inner pattern lines up perfectly with my 904 converter. I didn't know if there was some other issue though since they were specific about which transmission its for.
It would be cool if that B&M for a Magnum was useable with a 904. All I've got is the stocker out of the Durango.