Pat,
72's may be different as far as how the jack mounts/stows but I know you have to use low profile speakers, like less than 2 1/2 inches, in order to avoid interferance issues between the passenger side speaker and the jack. If your jack stows the same as the 78, under the package tray, you might want to test fit it before you get the rear seats in place just in case you have to change speakers.