fuel pump draining back to tank

Your check valves are leaking. This is what I use with a dead head regulator and 3/8 fuel line from the tank for steady 1/4 mile WOT flow. Summit regulator is set to 6.5 psi OOTB.
Carter Strip Super Mechanical Fuel Pumps M6270
Carter Strip Super Mechanical Fuel Pumps M6270
That's actually what I was thinking. I have a Quick Fuel HR-650 on it and it's great, but I was told no more than 6psi of fuel pressure. So if I go with the Carter I would need a regulator, right?