Finally found the right bypass air hose.

[cruiser]

For whatever its worth, I finally found the correct looking air cleaner bypass hose for my 1974 slant six Duster. The original hose (which goes from the heat stove on the exhaust manifold to the bottom of the air cleaner) was completely shot because it was made out of cardboard, and five decades of being exposed to everything under the hood ruined it. NAPA sells a nearly identical hose and since any NOS unit that you find will be pretty brittle, this may be the right one for you if you're going for that correct vintage look. The photos below show the hose and its box, then a close up of the actual hose. It looks just like the factory original, with a paper outside and a metal foil inside. The part number is NAPA 825-4026 and cost me about 15 bucks. You cut it to length, and after I removed the bottom 2 1/2 inches it fit perfectly into the 2" round housings on the manifold and the air cleaner. Just thought I'd pass this along - might save you some time searching around. Thanks - cruiser

 

[cruiser]

Oh yeah, one more thing: When I went to install it, I noticed that there was a slight ridge about halfway up the circular mounting base that the hose slides over on the underside of the air cleaner. This ridge isn't parallel to the base, but curves upward slightly. After struggling a bit to get the new duct onto the bottom of the air cleaner, I finally figured it out. This ridge curves upward slightly so that you can thread the duct onto the mounting surface, instead of just pushing it on. Once I started "threading" instead of "pushing", it went on easily and looked great. Yeah, I know - probably TMI (too much information).