Are 727 and 904 converters the same?

The spline count and input shaft diameter is different between the 904 and 727. Besides, you will need an externally balanced torque converter for the 360. There is a lip in the transmission tunnel at the firewall that you will need to flatten out for the 727 to clear the tunnel. You will need a V8 center link for the steering and a center sump oil pan. Exhaust will also be a major PITA. Those are some of the reasons I decided to keep the slant in my '66 Valiant.