Stainless rigid tubes are great. Lycoming lists 4 different ones. Most all are the same fromt he case nose around the sump to about the engine mount ring. Depending on what fitting is in the accessory case for the, tube (straight, 45* or 90*) thats where the difference is. Angles, lengths. Unless you are replacing a rigid tube that you KNOW fits your engine, it might be easier to use a firesleeved teflon hose.
WE have 1 of the 4 tubes scanned for duplication---but dont really have an application for it. Eventually, we'll have a pic of it on our joint venture website.
Tom