273 torque converter
Do you still have the 5.9 Magnum flex plate that came off of your motor? I am not sure if a 904 converter will bolt to it or not, but I could check for you tomorrow if you'd like. I have the factory flex plate from my 5.9 Magnum and a few 904 converters laying around to check with if yours isn't out of the car where you can get to it.