Fuel hose AN6 or AN8

There would be no, or less restriction to the flow.

I thought that for an application such as the OP's car the idea of the return was to circulate the fuel and reducing the temps? Not that 500hp is anything to sneeze at but for this application the flow will be without factoring in an equal to size for both lines.... I may have gotten a touch smarter on the subject lol.....

JW