I was a 4-7 in the rear I had shock extenders and I used air shocks ran the lines out the bumper so I could air up when I had load or leave a little air in rear for smooth ride
I know you said no shock extendors but I ran some from djm along with orieleys air shocks and my truck Rode like a dream its was 4-8 and I could pull my pop up camper all over Texas with it