One of the jobs I plan to do this year is to change the heater trunking on my '73 westy. A PO removed the rear Y piece and the centre tube and replaced with some sort of steel flexible industrial tubing. This goes from the heat exchangers to the bottom of the front totem pole with a 90 degree joint just before going down the centre of the bus. I want to get back to standard if possible. Should I get new (repo?) or are original bits arround? I'm led to believe fitting a standard Y piece is a swine to do but I've seen somewhere it can be split up tp make smaller and easier. All advice/comments gratefull recieved. I thank you.