I think that is it John. The tag on the box is labeled "1969-78 Chrysler C Body." I searched the website for the 1970 300 carpet and the part number is that same as for my car. Are the additional four inches of your wheelbase added to this section of the car? Thanks for the picture and the measurement.
I tightened the bolts on my seatbelt assembly tonight and it measures about 11.5 inches from the center of the hump to the shelf. I'm attaching a couple pics to rule out that I am installing the seatbelt wrong, but I am pretty sure it is correct.
View attachment 125124 View attachment 125125