Calling all 67 to 69 Valiant owners

According to this http://www.hamtramck-historical.com/_PassengerCarBumperHeights-01.shtml?load_img=10 the rear bumper height should be around 11" and I'm not even close so I'm trying to figure out how to get it there or somewhere near that right now I have Mopar XHD springs on it with the smallest tires I have and even let all the air out of the rears and I'm about 5-6" High

Thanks