[Batman]

What leads you to believe it is a bad pump? Check the fuel pump lead positive wire make sure it didn't come loose and hit the headers when you did the install. The fuel press gauge does work but with the big pump and oversized injectors if you see it dropping you have a problem. The fuel pump isn't very old and it is a racetronix pump so I doubt that is the issue unless it is a wire. Also when you put the headers in and had the starter out you may have pulled a wire out of the crank sensor. It happens alot. Only way to get it to throw a light is to crank the engine for 30-45 seconds and see if it throws a code or pull the starter and check the wires/plug