Where is a fuel pressure regulator on a 5.7 vortex engine?

Vortex engine? Got me. I thought Vortex was just a brand of supercharger.

I believe you mean Vortec engine.. GM also called this the L31 (they use 3 letter/number codes for everything)

This system used a SCPI (Sequential Central Port Injection) system... and the fuel pressure regulator is on the central unit, which is INSIDE the intake manifold- you have to remove the upper intake manifold to get at it (plastic part), and the Fuel pressure regulator will be on one side of the central unit where all the fuel lines go to, it has a tube on it open to the intake manifold (to read intake vacuum)