I have an original one that looks it was all one piece from the factory. A steel line comes out of the T Block and over the timing cover. Then it looks like a flex line is factory crimped to the line. There is about 6" of flex line that ends in an EL fitting with a flare to go to the filter housing. When these lines were still available from GMC, I never remember replacing one because they never broke. I looked at a couple of my old GMC's and they seem to all have some kind of jerry rigged flex except for the one that I know to be original. I know there is a restricter in the line somewhere. I think it is at the end of the flex line which would put full pressure on the flex line. I'm not sure if anyone makes reproduction lines. I'm sure a NOS would be just as rotten as what I have one mine. Our Cummins Diesels use a stainless steel line for oil to the turbo. I think it could be adapted to work. It's not a fun thing to work on because the line is crammed in behind the filter and the lower radiator hose.