The metal tubing with short rubber tubes attaching is common in race cars.

My old 59 Ferrari was that way too. There were metal tubes everywhere, hand made, sometimes lovely y's and headers made up and final connected like you are planning there with a short section of straight tube, or sometimes a curved section.

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.