Today I installed the Holley fuel pressure regulator with gauge. My mechanic did set it to 3,5 psi, but everytime I start the engine, the gauge needle jumps around and doesn't stay near 3,5 psi at all. Guess it is because of the vibrations, but I've seen other CJ owners with similar regulators also mounted on the engine. My engine works great. No problems at all.
Here is a short video:
And some pics: