Holley Carburetor Ultra XP 650 CFM Aluminum Circle Track-4150

When it comes to a 650 CFM opening, the Holley Circle Track-4150 Aluminum Ultra XP Carburetor (0-80812BKX) pushes airflow through quicker and more efficiently. The lightweight, aluminum is constructed for Circle Track-4150 calibration and features an anti-siphon valve in the main body. After construction, the aluminum is protected by an anti-corrosion coating that shines next to the black anodized billet aluminum metering blocks and base plate.

Features and Benefits:
- Aluminum Construction (saves 4.5 lbs - 38% weight savings)
- Shiny Coating with Black Anodized Billet Aluminum Metering Blocks/Base Plate
- Calibrated specifically for use on Circle Track
- Base Plate Set Screw for Wide Open Throttle Stop Adjustment
- PTFE Coated Throttle Shafts Rides in Oil Impregnated Bronze Bushings
- Anti-Siphon Valve in Main Body Reduces Pump Pullover
- Contoured Venturri Inlet Offers Balanced Airflow for Increased Horsepower
- Smoother Airflow Transition as Air Bleeds move Outward
- Metering Blocks Feature Improved Durability and True Gasket Sealing
- Fully Adjustable Emulsion Bleeds, Power Valve Channel Restrictors & Idle Feed Restrictors
- Dual 30CC Accelerator Pumps for Fuel from Idle to Full Throttle
- 20% Fuel Capacity Increase w/ Slosh Control and Internal Baffling
- Clear Sight Windows on Bowls for Quick and Safe Fuel Level Adjustment
- Built in Drain Plug in Front Center of Bowl for Easy Disposal
- (-8) O-Ringed Inlet Threads for Versatile Plumbing Application 
- Precision 4-Corner Idle System
- Accelerator Pump Tuning via Metering Block Internal Pump Passage Bleed Off
- Knurled (Hand Adjustable) Primary and Secondary Curb Idle Screws
- Primary throttle shaft capped to prevent entry of debris & contaminates
- Set up with 1:1 throttle actuation
- Includes wedge floats

*Baseplate designed with a boss that can be consumer machined for vacuum source.
*The (-8) O-Ringed Inlets comes from the factory with 8AN inlet fittings.

The high capacity fuel bowls hold 20 percent more fuel capacity, which eliminates starvation and offers an integrated fuel shelf that minimizes fuel aeration and internal baffling to control fuel slosh. Other features include wedge floats, adjustable secondary linkage and knurled (hand adjustable) curb idle screws built for the square bore design. An integrated idle bypass valve eliminates the need for holes in throttle plates and allows for proper adjustment of idle while maintaining correct throttle plate to transfer slot relationship to maintain good idle control when using radical camshafts.

Please Note: This model of carburetor has the square bore flange bolt pattern. It can replace Holley, Edelbrock, Carter AFB, and Autolite style carburetors with 5-3/16" x 5-5/8" bolt pattern. If you have a spreadbore style intake manifold, you will need an adapter to install this carburetor.