1966 904 to a 1965 904 Transmission swap into a 65 Dart

Some of the 66 parts will fit the 65 trans, some will not.
All of the V-8 and /6 internal parts will interchange between the 65 cases. The number of clutches, may or my not be the same.
If you use the 66 trans, you will also need to change the drives shaft.
If you are not familiar with the internals of the 904, your best bet is to rebuild the 65 tf904 that fits the engine (slant or V-8, not sure whichengine your using).