[JSeery]

I use return lines on all of my high pressure installations, but seems like overkill on a low pressure setup. Vapor lock should not be an issue on a flathead with an electric pump. The pump is pushing the fuel not pulling it (assuming the electric pump is mounted low and near the tank). It is the pulling on the fuel that is the major component in vapor lock. The stock pump is mounted high in relation to the fuel tank and has to pull the fuel up to the pump. Add in the heat where the pump is located and it is an ideal setup for vaporizing the fuel.