Those Holley regulators are crap. I never could get the fuel pressure right on my old GLC. Jeff20B's cheap regulator (I think it might be
this one) seems more consistent. I'll be using a
rebranded Aeromotive 13301 on my blow-through DCOE project. I'll let you know how it works.
Edit: Apparently Jeff's is actually a Purolator, but I think the Spectre and Mr. Gasket ones are the same.