My '53 recirculating heater takes a 2" diameter hose on the driver's side and an 1 3/4" hose on the passenger side. The dash vents on both sides are the same size - 1 3/4" and that's why the driver side uses a rubber adapter so the 2" hose will work. Chevy's of the 40's sells both size hoses in the original type fabric.
