My otherwise stock K3500 diesel has an aftermarket auxiliary tank. Electric 6 port selector valve shifts both the supply and return to the tank you select.

1957 Chevrolet 5700 LCF 283 SM420 2 speed rear, 1955 IH 300U T/A, 1978 Corvette 350 auto, 1978 Yamaha DT175, 1999 Harley Davidson Softail Fat Boy