Need help to ID a 727 Torqueflite

I have a 727 torqueflite that I know either came out of an A or LA engine car...the only information that I have is the serial number on the driver's side transmission rail. It reads as follows: PK 3898867 5432 5375 . I would greatly appreciate any help with this. Thanks....Steve....by the way, I am putting it up for sale if anybody is interested......