Vapor Lock Fix ?

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I am having a vapor lock problem from vacuum tank to carb. Has anyone used a wrap of sometype to wrap the fuel line that helps from vapor lock ? Also was wondering if I use a straight in fitting to the Marvel carb. instead of "L" to get the fuel line lower and further away from the heat riser pipe from the exhaust to the intake madifold or is the "L" fitting needed for the fuel flow to the carb.? Thanks Ron