Holley 4BBL Vacuum Secondary 600CFM Stage 3 – 1850S3





  • Metering blocks are hand selected and all circuits and passages are checked for casting flaws and obstructions, as well as proper sizing
  • Metering block design is selected based on your engine combination
  • Matched boosters are installed, then aligned and centered in the venturi for best flow and signal
  • Floats are modified based on applications, drag float, single taper, double taper
  • Choke tower is removed with Bridgeport vertical milling machine to increase air flow, and balance air flow of primary and secondary venturis. This promotes increased high rpm horsepower. This is a no cost option however an optional electric choke can be
  • Carburetor is assembled using only the highest quality components, including reusable gaskets for ease of tuning and service
  • Booster design is chosen based on your engine specifications, then balanced and modified for increased signal strength and atomization characteristics, providing crisper throttle response and driveability, as well as increased HP and TQ thru-out the rpm
  • All components are then vibratory tumble polished and dichromate coated for a brilliant high gloss gold finish
  • For classs rules that do not allow secondary metering blocks. We install a secondary metering plate that features; removeable standard holley jets, adjustable transition circuit and increased fuel delivery.
  • All vacuum ports plugged
  • All choke hardware removed and openings plugged
  • All body surfaces machined for maximum gasket sealing, ensuring consistency and reliability
  • Balance all metering passages, then resize and modify for optimum fuel curve, including:
  • Emulsion, High Speed Air Bleed, Idle, Idle Air Bleed, Main Well, Main Well Exit, Power Valve, Transition

Additional information

Weight 15 lbs
Dimensions 15 × 15 × 15 in


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