You might be able to poke around on Google and find replacement seat springs. I know that I have seen them at some of the restoration supply vendors that come to shows like Good Guys, The Turkey Run, etc. They look like the ones in your pic, but come in cut to length versions. I was glad to be able to work it out so you could have the vent tube. I got the fill tube from Al as an extra to do a science project for my own 65 Barracuda. :)