I just finished this procedure yesterday. Took my own advice and used 5/8 fuel line. It's plenty stiff and won't kink. Heater hose is not "officially" rated for fuel or fuel vapor resistance so it would fail California smog. I do it all the time. It does soften up and could collapse under ...

I'd use 5/8" fuel line for better oil resistance. Heater hose will fail a California smog check if the tech notices.