I am doing this on my 71 Demon 440 727. I don't believe the 904 linkage will work, I bought the linkage for an a body with 727 and when I mocked it up I'm about 99% sure it is going to work fine. The only concern is to make sure the trans has the hole on the forward left side of the case for the column shift bracket and isn't for a floor shift. The linkages are starting to get harder to find. Also the type of headers you run will have an effect for the torque arm coming across from the frame bracket to the transmission. Sorry I didn't take pictures of it when I mocked it up, and I'm slowly getting the car together so may be a bit before I'm at the point of installing it. There are others here that have theirs completed and will chime in.