Geoff, I think you may have to compromise on the pipe, I would think you could use VW beetle air hoses on it, they are formed of aluminium foil and concertina. If you can get the right size and shape you could them wrap them in exhaust bandage to get something close to texture maybe?This is the air cleaner pipe I am looking for, mine is getting fragile, the plastic strap beside it I believe are unobtainable, the last one I saw on a car was mine!! but I think these could be easily 3D printed if you know anyone with a printer. The pipe is wire reinforced but made out of some sort of paper/cloth/cardboard material, I see yours has writing on it, any chance of there being a name. It has a 55 mm internal dia and is about 460 mm long, tried a few places but no joy. I like you am trying to keep original.
I stripped all the rear off my car last year powder coated and re-bushed all new springs and shocks etc. On mine there is a rubber fuel pipe that goes from the tank across the car which you can now get to with the suspension off, it's a good idea to replace this while you are in that area.
I will sort out some Montreal pic's later, but have to warn you that it's my project and been going on for a while