727 transmission questions

I'm installing a rebuilt 360 into my 73 dart swinger. The car currently has a 318 and a 904 trans, and I'm wanting to put in a 727. I have a balanced flex plate for the 904 as the 360 is externally balanced but changed my mind as a 727 will be able to handle the power better.

The 360 came with a 4 speed manual out of a truck so I don't have a torque converter. The 727 has a converter I think but I'm going to get a different converter.

My main questions are, can I buy a weighted torque converter and not use a flex plate? And what can I use from the 904, does the flywheel fit? And because it's a small block going in I assume the bell housing is interchangeable from a 904 and a 727? I think I have a flywheel but I haven't really looked at the 727 too much yet.

This is a pretty easy swap I've been told, I hope I was told correctly, if not should I just upgrade my 904 to handle more power?