I have a 89 camaro with a 350 engine, where can I find the fuel valve where I connect the fuel pressure tester? I looked up videos on where it's located but mine doesn't seem to have it, is there another way to test it like removing a line and connecting it?
As long as you have Tuned Port Injection (TPI), the Schrader valve is located at the back of the fuel rail on the passenger side (near the distributor). You have to use a 90° elbow in order to attach it, because the upper plenum sits right over the top of it. If your engine is carb'd, you'll not have one.
EDIT: Here is a little broader picture of my own personal 86 Camaro IROC-Z with the TPI. In the picture you can see the distributor at the back center, with the intake manifold ahead of it. The two intake runners for cylinders 5 & 7 are plainly visible. The injectors for 6 & 8 have green arrows pointing to them. The rail is sitting right on top of these two injectors. The Schrader valve has the red box around it. The cap is present on this, yours may not have it there or it might. If the top of your engine does lot look like this, you do not have a TPI system in your vehicle. We'd need a picture of your intake and engine to decipher exactly what is going on.