you probably want to find a t4 .91 a/r divided housing. The undivided .88 is actuall bigger and slower spoolin than the .91 a/r becuase its not divided. The best option would be a t3 housing, unless you are wantin just to drag or pullin. I know a few people on cummins forum that have run the divided .91 a/r with a spool flange from sdx. If you daily drive at all i would find a t3 and have it machined, or jacob at diesel auto power is workin on a 100% borg warner with t3 housing. There is super informative threads on this over at cummins forum and probably here also.
