fuel pressure regulator

My dad has a 2000 Chevy 3500 with the 454 in it. I starts hard all the time and I was told it is the fuld pressure regulator but I can't find it anywhere on the engine. I know where it is on my 2000 5.3, but can't find it on my dad's truck. The fuel pump was replaced about a year ago so I don't think it is that. Any help would be great!

You will have to remove the upper intake to gain acces to the fuel rail and the regulator