Fuel return line replacement (1 Viewer)

[AFei]

Hello mudders,

While fighting with the gas tank boiling issue, I'm thinking to relocate the gas return line, which is directly bolted to engine, to higher location away from the engine.

Question is what fuel hose to use? Can I use J39R7 or has to be J30R9? ID 8mm 5/16"?

Thank for help.