Fuel Valve Leak Around Threads

[bdtutton]

Hello,
I have a 1930 Tudor and i decided to replace the fuel valve because it was leaking a little and the inside of the car smelled like gasoline. I replaced the valve with a nice new one. The problem I have is that I tightened it as tight as I thought it should go....I did not want to split the fitting on the tank....and here is my problem....it leaks around the threads. If it wasn't gasoline I would just use pipe tape, but I heard that would quickly deteriorate.
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Is there any type of pipe thread sealing product that can be used with gasoline?
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Thanks...