[71blksuper4x4]

On my crew with the cab & chassis frame, the frame is straight from the kick up back. After spending about a week researching and thinking it through, I am using the 73-87 3/4 ton spring hangers. Since I am using the the AAM 11.5 rear I have to relocate my axle perches anyway so gaining an inch in width on how far out the hangers sit won't bother me. (5.5 " out from frame vs 67-72 4x4 4.5" and 73-91 k30) I think your best bet is to use the k30 hangers personally. They will fill the frame rail closer as the 67-72 style only filled half of my modulus portion of frame. JMO. I needed the longest drop hanger I could find to match how much taller my frame is compared to the longhorn style frame rear. The duramax furthest rear hanger is about an inch lower 10" to the 73-87 k20 9". 67-72 furthest rear is 6" drop. The duramax ones can't be used as they are 4" out in front hangers and 5" out on back ones to account for the frame overlapping they do on the new frame rails. Just trying to help as I have been there and weighed all options out.