That's a C body part number with a 70 date code, 0260, 26th day of 70. Does it look like it ever had a label over it? Chrysler often put a C body part number on a car and put a vinyl sticker over it with the correct part number and vendor code.
The 3431077 for the E bodies had a Yellow tag and the 2983116 motors had a blue tag with the correct part number and vendor code