Adjustable regulator if it has a screw in it?

[Nicoleb3x3]

I got a hande me-down fuel rail and FPR when I did my 5.0 swap.
My car seems to be running a bit rich, and I wonder if my fuel pressure is too high? I get black spots on the pavement at my tail pipes.

How can I tell if my FPR is adjustable or if it's the stock version?

the only reason I question it, it sbecause it had a screw in the top of it....were the vacume lines goes. I removed the screw and have the vacume line there like I knew it should be. But I'm wondering now if that screw was there because it was an adjustable version?

here's pics of it installed in my car (the screw is removed now like I mentioned) sorry the pics aren't better

 

[bill302]

looks like a stock from what i see and was the screw in the vacuum port before you installed to keep trash out of it? and it should have the manufacture name on top of the regulator and part # on the side...heres a picture of a non adjustable
View attachment 460262

heres a pic. of an adjustable fuel pressure reg.

 

[Nicoleb3x3]

it appears to me that it is a stock one...but why the screw in it? ...I assume it's ok that I took it out and put the vacume line on it.

I assume the previous owner had the screw in there to bypass the vacume system? but why?