yes this is true but 1/2 3/4 and 1tons all have the same with to them untill u get in to rv's and cab and chassies, then the with starts changing with wise. as for the hanger being larger then the stock one thats a given, because 2wd hangers r only 8 to 10 inches long and so r most blazers, but the the full size 4x4 trucks on the other hand have a hanger which is the one we make, is 16 inches long or so, but the three inches that the spring sits off the frame is the same on half tons, three quarter tons and one tons that R NOT CAB AND CHASSE AXLES. gm made all there frames there frames the same with in the rear for one simple reason so they could use the same axle in 73 as well as in 91. yes gm did make small changes to the axles like extra bump stop pads in the later model 10 and 14 bolt axles but the spring perches didnt change with wise from 73 to 91 in sub., blazers, crew cabs and in the stander cab log and short bed trucks 73 to 87, if u dont beleave me find anther truck and messure the with of the frame rails in the rear and mesure the depth of the hanger from the frame rail and post it back on here and ill check my truck and ill bet u a set of my spring hangers that im right.