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NOS Pro Two-Stage Wet Nitrous System for 4150 4-barrel Carburetor-Black

Fits Holley 4150 and Carter AFB (late), 200-500 HP, includes Black 10 lb Bottle


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NOS Pro Two-Stage wet nitrous system gives you a moderate shot of nitrous at the line to get a solid start. Then, a second stage of nitrous gives you serious muscle through mid-track and the top end. This system is adjustable from 200-500 horsepower and uses a special dual stage plate design for excellent nitrous flow, fuel atomization and mixture distribution. Our Big Shot style Pro Two-Stage plate utilizes 4 unique spray bars equipped with tiny orifices precisely located to efficiently dispense a powerful nitrous/gasoline mixture for unbelievable horsepower gains.


  • Includes 4150-flange 1” thick dual stage black aluminum plate with 4 spray bars
  • Offers steady and precise nitrous flow, fuel atomization, and mixture distribution
  • Includes jetting for 200, 250, 300, 370, 420 & 500 horsepower
  • Includes 2 Cheater Fuel and 2 Cheater Nitrous solenoids
  • Bottle is made from 6061-T6 Aluminum
  • Includes 10 lb. black nitrous bottle with brackets
  • Includes mounting hardware and instructions


Bottle ColorBlack
Bottle Size10 lb
Brackets IncludedYes
Delivery StyleSquare Bore Plate
Emission Code4
Feed Line Size6AN
Fuel SolenoidCheater
Included Jetting Horsepower200, 250, 300, 370, 420, 500
Jet StyleFlare
Max Horsepower500
Nitrous SolenoidCheater
Number of Solenoids4
Number of Stages2
Plate Flange4150
Plate Height1 inch
Product TypeNOS System
Solenoid Top Cover ColorBlack
System StyleWet
Part Number02301BNOS

Service Parts



This part is legal for sale or use on Racing Use Only Vehicles

The following vehicles are considered Racing Use Only Vehicles:

  • Racing Use Only Vehicles are vehicles that are used exclusively for competition that are not registered and that may never be used on the street

WARNING: It is against the law to install this part on an Emissions Controlled Vehicle

Tech Resources

To supply the proper amount of fuel to the carburetor and the Big Shot System, a fuel pump must be used that is designed to operate between 4.5 and 7 psi, with a flow rate of 0.1 gallons per horsepower at 6 psi. For example, an engine that produces 350 horsepower when the Big Shot System is activated will require a fuel pump that flows at least 35 gallons per hour at 6 psi.
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