1975 904 for slant 6

So I looked up Florida Torque Converters and they list a 1975 904 Dodge Slant 6 as a 11''.
I also checked for a 1971 as that is what I have and it shows the same converter part # 12-3
Part # 12-3 $289 with a $100 core charge.
I'd call 800-790-0039 for assistance.