Check Valve

[SAYBYE]

Hi guys I'm working on my buddies 79 he wants to use both and electric and the regular one. He wants the electric one for startup and to avoid vaperlock. I have it teed in before the regular pump and before the fuel filter by the carb. I have a fuel filter before the electric pump. I wiered a starter switch so he can push it until the carb is full then turn the key. Problem is the fuel runs back down the reguler fuel pump, and not into the carb. That is why I'm looking for a inline check valve. Thanks for any help.