I am doing a swap with a motor from an 02 denali and I need to know if the regulator is mounted on the motor or is located in the fuel tank with the sender.

 

The fuel pressure regulator is located on the driver side fuel rail.

 

Yup , which is fine if you are putting it in an 99-03 truck. The '04 and newer have a returnless fuel system with the regulator in the tank.

 

On the return side?

 

In the center of the driver's side fuel rail on the intake. It's round with a vacuum hose going to the top of it

 

whoa whoa whoa not to hijack by no means and this might help you also . how do you adjust your pressure on 04 and up . also what are the major downfalls to this and psotives

 

So this brings me to my next question. I have a walbro 255 intank pump. Is the stock regulator going to be OK with that?

 

04 and up don't have an external regulator, it's a returnless system. As far as adjusting air/fuel ratio or injector duty cycle or anything like that, you would need the proper tuning software to do so.

Not sure about the walbro with the factory regulator...you'd probably want to contact walbro on that, I'd assume that they'd have their own heavy duty style reg, but I'm not sure.