what will a adjustable fuel regulator on my 97 7.3 liter do performance wise

 

Nothing. If your pressure is droping now you can shim the FPR or go with electric fuel that would make it so the pressure wouldn't drop and you might gain 1-2hp depending on how much the fuel pressure is droping

 

What is your fuel pressure at idle? Have you checked?

 

no never checked what signs do i need to look for for the pressure at idel

 

You need to check your fuel pressure at the schrader valve on the side of the fuel bowl... You can use a tire pressure gauge. Just have a rag handy because it will spray a little. Do this while the truck is idling. Let us know what that number is.

 

what if its regular or below pressure how can i increase it

 

You want right around 65-70 psi at idle... But you don't want to go much over that or you will start taxing the fuel pump heavily.

If it is below 45ish, you can shim the fuel pressure regulator with a bb and it will increase the fuel pressure.