Abstract: An exhaust aftertreatment system including a housing with two or more inlets configured to receive separate entering exhaust streams from an engine. The system may include two or more first exhaust treatment devices, each configured to receive one of the separate entering exhaust streams in a first direction. The system may further include two or more redirecting flow passages configured to combine the separate exhaust streams into a merged exhaust stream that flows in a second direction about 180 degrees from the first direction and an intermediate flow region configured to divide the merged exhaust stream into two or more separate exiting exhaust streams. The system also may also includes two or more second exhaust treatment devices, each configured to receive one of the separate exiting exhaust streams in a third direction about 90 degrees from the second direction.