where can i buy a 904 tail Shaft Seal for my 273

The 65 trans has a flange that bolts onto the output shaft, just like the 64 trans. However the bearing and seal at the end of the tailshaft housing on the 65 trans is different then the 60-64 parts.
The part number that is listed in the screen shot (2464 482) is correct for the 1965 trans. Fatsco is used to be very good at supplying the correct parts for the obsolete transmissions. When I lived in NJ, I delt with them on a regular basis, but that was 30 years ago. I haven't bought from them for a few years, so don't know how they are now.
These are pictures of a 1965 trans https://earlycuda.org/techdocs/ConvertFrontUJoint.pdf