This was "supposed" to be an LA plant item only for cars with power brakes, but I have found it on two NOR cars with power brakes. The original GM part number is 6291392. I had talked to Tom at M&H back in the early 90's about this harness and he told me that cars with power brakes really need this to make routing the harness easier. He confirmed that GM showed it to be an LOS item only, but like me he has seen it on NOR built cars also, and all had power brakes....................RatPack.........................