Low fuel pressure

[Mathew21]

This is my first engine swap. I have a 1966 Chevy C10 with a 5.3 from a 05' Silverado. I have only 36 lbs of fuel at the schrader valve.

I installed a under the bed Boyd welding tank that came with a Aeromotive Stealth 340 Fuel Pump. I ran 10 gauge for the power wire and 10 gauge for the ground wire.

I ran 5/16 fuel line from the tank to a LS1 Fuel Filter/Fuel Regulator from Speedway motors. The return line from the regulator to the tank is also 5/16. The fuel line from the Regulator to the fuel rail is 3/8.

My first mistake I made was I reversed return and feed fuel lines at the regulator. After I figured out I barely had any fuel pressure I switched them around. Now I only have 36 lbs. Is it possible I damaged the regulator?

Any advice you can offer this newbie sure would appreciate it.