How to tell what my transmission is without removing it?

I have a 1964 Ford Galaxie. I was told it had a C4 but I have reason to believe I was misinformed. The motor that was in it was not original, so i'm assuming the transmission was as well. BTW, the motor was a 351W.

Added (1). I counted 16 bolts on the pan. According to a form I read, it said the C4 has 11 bolts on the pan.

Added (2). I don't believe the transmission is original to the car

Added (3). The original motor was a 352, the motor taken out of the car was a 351W. I assume the original transmission wouldn't fit the 351W.

Added (4). The car is automatic

How to tell what my transmission is without removing it

Sounds like a fmx trans a 352 trans won't bolt to was probally a cruise omatic(c-6)originally the bell house pattern is different

It may be a FMX or Cruise-o-matic transmission if it is original. I don't think they started using C4s in full sized Ford or Mercurys till 1966

You can probably find out by looking up VIN decoders or look at it and look at images of transmissions for that make and model and see which one looks right, look for a serial number on the transmission housing ETC