I bought a Holley 12-803 Fuel pressure regulator to knock the fuel pressure down to 6 psi. It won't even go down to 7 psi. It's supposed to be able to drop as low as 4.5 psi. What is the problem? I asked Holley but they will not reply.
If you have everything connected properly, and are doing the adjustment properly, perhaps it is a defective piece. Some imported automotive items these days have problems. Perhaps you should approach the seller.
The Ford truck shop manual for 1976 says the mechanical factory pump should have a static pressure of 5.0-7.0 PSI on the 460 engine.
Kind of thought it was bad. It's a Holley made in China. I'm also using a Holley Red electric pump. It puts out 8-9 psi and I can't set the floats on my Holley carb. 6 psi is what I'm looking for.