[Southcity]

Thanks lownslow64. My understanding of the design on the original tanks is that the smaller tube which leads back to the main fill tube (terminates just below the gas cap) is to help prevent gas from splashing back out (fill pressure) when filling the tank. If using a stock style fuel pump, tank pressure increases/decreases when driving, when ambient temperatures change etc. A vent is required somewhere to help with this, in stock form I believe the original gas cap was vented. My current gas cap, even though it's aftermarket, is also vented and helps with this. The only issue I have from time to time is a small amount of gas seepage from the vented cap if tank is more than half full and I take some hard turns.