I have 2 push rod tubes (imagine that) that I can't get to stop leaking
One problem might be I have the old 70's heads the have the smaller openings so the "O" rings that you would get from the bird are two big. I found "O" rings that are exactly the same as the original ones I had (they old are shot or I would have reused them). I am not about to go and have the heads bored for the normal size tubes and then purchase new tubes. I was thing about puting the "O" ring back on and wrapping the "O" ring and tube with some of the rubber electric tape (the kind you stretch and it adheres to itself) then hopefully I will get a tight fit. It really suxs have a smoke screen behind you (unless the police are following).

You can get O-rings in the correct size for the early 1970 heads. Stock silicone ones, at least. Mister PET says: 021 109 349 SEALING RING; 23,5 MM FORPROTECTIVE TUBE RED

You can probably find a Viton O-ring of the same size, but you'll have to hunt through industrial supply catalogs for it. Or just use stock silicone O-rings and live with the notion that they may not last as long as you would like.

--DD

Dave's answer seems easier, doesn't it? I have the seals in stock (somewhere). They come in the gasket sets and hardle ever get used. The Cap'n