2. Another key piece to Holley’s billet HP lineup is this billet fuel pressure regulator (PN 12-845). On par with many billet regulators pricewise at $150, Holley’s HP unit is precision machined from 6061–T6 billet aluminum, and features a black bright dip anodized body and a clear bright dip anodized top for corrosion resistance and good looks. These regulators are available in a variety of configurations, and are adjustable from 4.5-9 psi for carbureted applications. This particular piece features a -8 AN O-ring inlet, a -8 AN O-ring outlet, and a -6 AN O-ring return. There is a 1⁄8-inch NPT gauge port as well.