Just converted my 89 to carb and in the process of getting it dialed in, I set the fuel pressure to 7 psi. When I started it up cold it was 12 psi. After driving for a while I checked again it was at 4 psi. I have a brand new Holley blue and pressure regulator with steel braided line from tank to carb. It is 3/8 line. I was told that this is ok but it worries me. Why is my fuel pressure fluctuating so much? Thanks