[Aussie Mike]

You don't need to run the LS1 pump and you can retain the stock LS1 fuel rails. Put the reg on the fire wall or in the engine bay. Run the high pressure feed to high pressure side of the reg and then on to the single connection on the LS1 rails. The low pressure port or return port of the reg runs to your return line back to the tank.

This way the regulator bleeds off the excess pressure from the main line to give you your desired pressure at the rails. The excess pressure and fuel is returned back to the tank.

I'll try to draw a diagram tomorrow if I get some spare time.

Cheers