a-904 transmission pan leaking looking for a new pan and am confused what fits a 1960 / 170

Folks, with the help of you folks, especially Slant6Dan, I have now completed the fuel system and the vehicle runs good.
My next concern is getting a new straight transmission pan for my 1960 Valiant 200, 170. I have replaced the gasket with a rubber one ( mistake ) and I have used Permatex as a complete gasket ( second mistake ). I read all I could on this site and find that there are supposed to be pans from Chrysler that will fit. I checked the numbers and find that they look different from my pan. It is a 904 automatic 3 speed tranny.
Are the new pans a little different? Are the gaskets also a little different?
The good news is I figured out how to look for the right area to start a new thread.
Your advice please. Hank