Fuel bypass question

The pump is being used how it is designed to, so it should be fine.Running a line back to the tank after the pump would just reduce the amount of fuel to the carb. Your best bet would be to run a true bypass at the carb with a full return line to the tank. A bypass valve has a spring/check valve that controls when and how quickly the fuel returns. Barry Grant makes an electric pump step down box which allows you to use large electric pumps on the street, it slows the pump down at low RPM's. I've never used one but anything from Barry Grant is a quality(expensive) product.