Add to Favorite Sellers. Holley 12-847 Dominator Billet Carbureted By Pass Fuel Pressure Regulator. Hot Street/Race Carbureted Applications Two Port Adjustable from 4.5 to 9 PSI; Holley® Billet Fuel Pressure Regulators are part of a complete line of fuel system products from Holley®. They are precision machined from 6061-T6 billet aluminum for strength and durability. […]