I put a fuel pressure gague on my motor, the one from Summit, and it reads at 13psi. I've never touched the TBI unit at all and I know that its adjustable from 9-13 but did GM really set it that high on some cars? I'm glad I didn't try to make it adjustable before I got the gague because obviously I cant make it any higher.

 

OK, I just looked at it again, first time I ran the car today. This time it was 15psi! To my knowledge that's out of range for the regulator right? I let the car run for about 5 minutes and it remained constant. When I shut it off the pressure dropped to 1psi. Is this normal

 

those gauges are only accurate at certain temperatures, when they get hot the liquid inside heats up throwing off the pressure readings. Yes that is normal. So when they are hot they will read low, when they are cold they will read high, i would let the car warm up for a few minutes and then check the gauge. That is what i do with mine. If you want accuracy, get an electrical gauge, but those things are pretty expensive.