Air bag help on stepside

[OARNGESI]

Hi i got a 70 stepside im thinking of adding air bags with a small step notch in the back and 2 inch lowering blocks . I did a little research on other threads posted here and found a post that said with a factory trailing arms that will hit the frame and leave my frame roughly 5 inches off the ground (i dont remember the tire size there). I measured today and as far as i can tell i have 22 inches from the bottom of the frame just above the springs to the top of the inside rear fender the trailing arms are 3 inches and my tires are 30 inches tall my main goal is to have the tires to tuck up in the fenders as much as possible without modifying the fenders. Is there any thing im misssing am i really far off any other suggestions. Thanks alot for all replies