ORIGINAL: joeflyer
The absolute best material is Viton. It will last indefinitely in fuel. It will swell slightly after soaking in fuel so make sure that you safety wire all connections. I get mine from McMaster-Carr.
Joe
I'm new to jets but in gassers we already know how well Viton works and long it will last. I used it in my first jet and it's perfect, no problems in this application either. As you know it is much more flexible than Tygon and the BVM clunk line stuff I received was very stiff in comparison to Viton as well.
McMaster Carr is a good supplier, if you don't want to hunt and only need a couple feet I would suggest Red Aero RC.... these guys are great and they certainly support the RC hobby.
[link=http://www.shop.redaerorc.com/Vitube-High-Performance-Fuel-Tubing-VT-1000.htm]Red Aero RC - Viton tubing[/link]
Steve