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Off Road - 680 CFM Carburetor

680 cfm Quick Fuel Off-Road Carb – Vacuum Secondary, Electric Choke-4150


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Quick Fuel Technology continues to lead the pack with their newest addition of Off-Road Carburetors. Quick-Fuel started, and is known for Custom Built or One-Off Carburetors. We have taken some of our proven specs and parts from past builds and used them to offer some "On the Shelf" versions of Custom Built Off-Road Carbs. Quick-Fuel carburetors are precision machined and hand-assembled by craftsman right here in the USA. Available in models for your daily driver to your competition-ready off-road truck or vehicle. The Off-Road series of carburetors are all made from light-weight aluminum components and are available in both vacuum and mechanical secondary models. They offer all the tunability that you would find from more expensive carburetors in the market, including four-corner idle adjustment, changeable air bleeds and tunable vacuum secondaries. Also an electric choke is standard on vacuum secondary models. Even though these are called off-road carbs, don't forget they are absolutely perfect for several other applications or uses – Demolition derby, stadium trucks, desert use, and mud boggers.


  • Proven Off-Road specs – calibrations
  • Available in both vacuum and mechanical secondary versions to meet your needs
  • All models have single inlet side-hung fuel bowls with sight glass windows for safe and easy float adjustment Side-hung floats offer better float control in off-road, off-chamber, or just a rough environment
  • QFT square Bowls are within 1 CC of the same volume of a center hung or V bowl. The square bowls offered by our competitors hold substantially less fuel volume than a V bowl or center hung bowl. Which affects the HP it can be comfortably used on. (No conc
  • Spring-loaded .110 Off-Road needle and seat in all versions
  • Single or dual line Carburetor plumbing option
  • Changeable idle and high speed air bleeds for easy tuning along with four-corner idle adjustment on all models
  • Vacuum secondary versions have adjustable secondary opening rate – (no cap or springs to change)
  • Cross-over vent tubes on vacuum secondary models for up and down-hill float spill-over control
  • Roll-over vent tubes on Q series models. These take the up and down-hill float spill-over control a step further while also preventing fuel spill in a roll-over. “Required for some stadium off-road and demo derby events”
  • Electric choke on vacuum secondary versions only
  • Compatible with GM, Chrysler, and Ford A/T kickdown linkage. Additional parts may be required
  • Hand-built and engine tested so you know it’s ready to go “right out of the box”


Billet ColorDiecast-No Billet
BoosterStraight Leg
BrandQuick Fuel
Emission Code3
FinishTumble Polished
Fuel InletSingle or Dual
Primary Main Jet70
Primary Power Valve65
Primary Pump Nozzle Size31
Product TypeCarburetor
Secondary Main Jet74
Supercharged ApplicationNo
Throttle Bore1-11/16 inch
Vacuum Ports2 timed spark, 1 full, 1 PCV
Part NumberOR-680-VS


This part is legal for use on Uncontrolled (Non-Emissions Controlled) Vehicles or Racing Vehicles.

The following vehicles are considered Uncontrolled (Non-Emissions Controlled) Vehicles:

  • 1965 and older U.S. manufactured California Certified vehicles
  • 1967 and older U.S. manufactured Federally Certified vehicles
  • 1967 and older Foreign manufactured vehicle

Racing Vehicles are vehicles that are used exclusively for racing or other forms of competition that are not registered and that may never be used on the street.

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        Some parts are not legal for use in California or other states with similar regulations.