Air Shocks 76 Dart Sport

So I finally got my air shocks on the 76 Dart, Not to bad, only about an hour to do both. Is it just me or do the Air Shocks of Today just not get as high as they used to. (see attached pics of before and after with max air pressure in them). I had a 72 Javelin back in the day with air shocks and before to after filling them I got almost a 8-12 Inch Rise out of them at the Bumper.

I like the rears of My Cars Jacked up, anything else I can do to this ol daily Driver to get some more height in the rear??? There's nothing in the Trunk right now for extra weight either but it only went up about 3-4 inches. UGH. Air shocks I am using are Monroe's.