I bought the the Top Downs Sulutions Fuel Pressure Reg and installed the silver spring that came with the package. I also drilled and tapped a different screw for adjusting. I'm not using the vacum port on the FPR because I didn't like the way it made the car act between shifts and forward and reverse. Well I understood that when you unscrew the screw it would lower the FP and when you screw the screw in it would raise the Fp. I wanted to raise the FP a little more than stock(around 13psi) but couldn't get it to go down. I unscrewed the screw all the way (no screw in it at all) and the FP is still 15PSI. I thought the silver spring was good for 12-20PSI. Any suggestions.

 

The spring is good for that WITH the vacuum hooked up. Since you are not using the vacuum to help "pull back" spring load, you are getting full spring pressure. You are only getting 15 psi because that is all the pump is putting out.

If you want a little more pressure than stock use the stock spring and shim it up with a spacer. I've heard a quarter fits about right.