[CompClassics]

The 427 comp cars used two Stewart Warner fuel pumps on one on-off toggle switch, they were mounted so that both were fed by the same port on the fuel tank for the reserve side and ultimately fed the mechanical fuel pump as a booster system only. The problem with this setup was that if one of the pumps shorted and blew the fuse both pumps stopped working. Once fuel pressure was present on the fuel pressure gauge the electric pumps were shut off and the mechanical pump drew fuel through them. The primary fuel line went directly to the mechanical pump. You would need a one way check valve on the reserve side to keep fuel going in the correct direction when using the primary feed.
If you are not using a mechanical pump, you can use two electric pumps on a on-off-on toggle switch to supply fuel to a “Y” connection but you will need two separate check valves so that the fuel does not back feed to the tank from either circuit. I’ll see if I can find photos of a dual electric pump, dual check valve system I did on a 4000 Series a little while ago. I also incorporated a electric fuel pressure sending unit that worked with an electric fuel pressure gauge.