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High-pressure fuel pumps, like NOS’ popular PN 15763NOS 110-gph Pump with Regulator (which is the same as a traditional Holley Blue Pump) are not usually provided with single-plate, single-stage carbureted N₂O kits; so why bring it up? Because most OE carbureted fuel pumps (mechanical or electric) function at a pre-determined output volume for stock engines. At three-quarter to wide open throttle, the OE fuel pump in your car is already operating near maximum capacity, so asking it to do any more than it was designed for is asking too much.

When purchasing a high-pressure carburetor-style supplementary fuel pump, there are four factors to consider:

1. The horsepower increase this supplementary pump must support.

2. The gallons per hour (GPH) required to support this increase in horsepower. (A common rule in determining the needed size of supplementary pumps is to multiply intended horsepower by .008 to .095 on a four-cycle engine like a Ford or Chevrolet small-block, or by .095 to .110 on a two-cycle engine like an ATV or motorcycle; and when it comes to alcohol, double these figures.)

3. You need to know the fuel pressure on which the engine operates. For carbureted engines like the aforementioned Ford and GM small-blocks, 6 to 10 psi is ideal.

4. The flow pressure of the pump under consideration. For example, the Holley/NOS pump is 110 gph, so your flow requirements should always be at or below the pump’s maximum GPH rating.

When mounting a supplementary carburetor-style fuel pump, it’s advisable to locate the pump as close to the fuel source as possible. Line size should be consistent with the remainder of the fuel system, and a high-quality fuel filter (preferably one that is serviceable) should be used.

Two types of fuel pressure regulators are available: deadhead or bypass. Regardless of which type of regulator you use, it is crucial that it is matched to the flow capacities of the fuel pump, or it could result in premature pump failure or burst fuel lines.

With a deadhead-style regulator, fuel pressure is controlled down to a set value using a diaphragm/spring arrangement that controls the fuel that passes into the engine. Once the system is disarmed or the engine shut off, fuel flow through the regulator ceases. If the pump is wired on a separate circuit, and remains on, line pressure climbs to the psi rating at which the pump stalls. This system is traditionally used on carbureted applications, so the previously mentioned Holley/NOS version is a good choice.

A bypass-style fuel pressure regulator controls fuel pressure by returning excessive fuel to the tank or back to the fuel line upstream of the pump. This particular loop approach reduces stress on the fuel pump by lowering the fuel pressure to the level at which the pump was designed to operate. Furthermore, fuel pressure is more constant with a bypassing regulator and the pulsing effect is eliminated. Bypassing regulator systems seem to work best with throttle-body injection (TBI) applications as well as sequential electronic fuel injection (SEFI) systems, which use either in-tank-mounted pumps, inline electric fuel pumps, or a combination of both.

High-pressure fuel pumps, like the popular 110-gph Pump with Regulator (PN 15775NOS; the same as the Holley Blue Pump) are not provided with single-plate single-stage street/ strip carbureted N2O kits, but they are a necessity.

NOS 150- to 250-hp Cheater system contains 150-, 180-, 210-, and 250-hp levels. It boasts a total of six 4-barrel applications, including Holley 4-barrel/late-model Carter AFB (PN 02001NOS), Holley Dominator and Barry Grant King Demon-flange (PN 02002NOS), early-style Carter AFB (PN 02003NOS), spread-bore flange (PN 02004NOS), and Holley 2300 2-barrel application (PN 02005NOS).

ZEX Nitrous Products bases its 4V single-stage single-plate N20 kits around its Perimeter N20 Plate, which features a series of finely drilled holes, referred to by the manufacturer as the Internal Delivery Channel. Horsepower increases of 100 to 300 hp can be achieved and ZEX markets kit applications in square-flange (PN 82040) and Dominator-flange (PN 82048) carburetor applications.

Nitrous Express entry-level single-stage, single-plate N2O system goes by the name Phase 3 Conventional Plate System, and is capable of producing 50 to 500 hp (PN 30040-10).

Nitrous Supply markets the NS Powerstar 8001 as an entry-level 4V, single-stage single-plate kit. NS’ fully adjustable jet spray bar plate is capable of producing between 50 and 175 hp with advertised torque increases of up to 195 ft-lbs. It’s a well-thought-out and well-designed kit.