65 dart tranny upagrade.HELP

All info is noted. Just so everybody knows, I will be running a 904 due to the fact that I have got a great tranny guy and due to space limitations. I guess I need to clarify my question though. I do know the pros and cons of both 904s and 727s. I have run both in a lot of different projects over the years. My question is mostly about any problems I will have with the upgrade. I am going to use an aftermarket shifter and the driveshaft will be an upgrade also. I will use an aftermarker performance stall converter as well a larger tranny fluid pan and larger cooler. The shift kit and manual valve body will also be in there. Has anybody done this upgrade in their early dart and what were the specific changes or mods that needed to be done to make this work.
Sorry if my first question did not have enough info. Everyone who has responded to my questions has been very helpful. This is my first early dart and I just need some insight from those of you who have been down this road before me.