Xtreme Performance - Holley 4150 ALUM ULTRA XP 750 CFM (Red)

Meet the Holley Ultra XP™ carburetors, designed for those who crave performance! These Ultra XP carbs are impressively up to 38% lighter than our traditional race carbs, while boasting a fuel capacity that’s 20% larger. With 30 innovative features, you’re in for a treat! You can choose from a striking Hard Core Gray™ hard coat anodized finish paired with a Black™ billet for added corrosion protection, or opt for a natural tumble-polished aluminum finish with your choice of Black™ or Red™ metering blocks and base plate. The Aluminum Ultra XP is available in sizes ranging from 600 to 950 CFM, including the popular 750 CFM option.

The Holley Ultra XP carburetors come packed with exciting features, such as an integrated idle bypass valve that lets you adjust the idle while keeping the throttle plate and transfer slot relationship just right. With high-capacity fuel bowls offering 20% more fuel, you can say goodbye to starvation issues. Plus, the integrated fuel shelf helps minimize aeration, and the internal baffling keeps fuel slosh under control. Other standout features include an all-aluminum construction, fully tunable billet metering blocks, a billet base plate, adjustable secondary linkage, and knurled (hand adjustable) curb idle screws. If you’re serious about racing, these square bore carburetors are the ultimate choice!

• Instructions for Part# 0-80803RDX
• Carburetor Numerical Listing for Part #0-80803RDX

• Lightweight aluminum construction (saves 4.5 lbs - 38% weight savings)
• Eye-catching red anodized billet aluminum metering blocks and base plate
• Perfectly suited for drag racing, circle track, or any high horsepower engine
• Contoured venturi inlet ensures balanced airflow for boosting horsepower
• Air bleeds strategically positioned for smoother airflow transitions
• Durable metering blocks with true gasket sealing, fully adjustable (emulsion bleeds, power valve channel restrictors & idle feed restrictors)
• Integrated idle bypass valve for easy idle adjustments without throttle plate holes, maintaining optimal throttle plate to transfer slot relationship - great for radical camshafts!
• Dual 30cc accelerator pumps deliver the right amount of fuel from idle to full throttle
• Fuel bowls with 20% increased capacity and internal baffling to manage slosh
• Clear sight windows on both sides of the bowls for easy fuel level checks
• Convenient drain plug at the front center of the bowl for quick emptying
• 8AN (o-ringed) inlet threads provide versatile plumbing options
• 4 corner idle system for precise idle control
• Mechanical secondaries ensure perfect launches off the line
• Elongated (dual pattern) mounting holes fit both square flange (Holley 4150™ style) and large flange (Holley Dominator® style) intakes
• Knurled (hand adjustable) primary and secondary curb idle screws for effortless adjustments
• Primary throttle shaft capped to keep out debris and contaminants
• Factory-machined accessory mounting hole for easy addition of adjustable primary throttle stop
• New secondary pump cam lever for a positive throttle stop on the secondary side
• Stainless steel adjustable secondary link allows for 1:1 or progressive secondary throttle actuation
• Baseplate includes a boss that can be machined for vacuum source
• Comes with notched float and jet extensions
• 100% wet-flow tested by Holley technicians to ensure it’s ready to run right out of the box!

• Barrels: 4
• Billet Color: Shiny with Red Billet
• Booster: Down Leg
• CFM: 750
• Choke: None
• Circuit: 2
• Emission Code: 3
• Finish: Shiny
• Fuel: Gasoline
• Fuel Inlet: Dual
• Material: Aluminum
• Model: 4150
• Primary Main Jet: 76
• Primary Power Valve: 6.5
• Primary Pump Nozzle Size: 32
• Product Type: Ultra XP Carburetor
• Secondaries: Mechanical
• Secondary Main Jet: 76
• Secondary Pump Nozzle Size: 32
• Supercharged Application: No
• Throttle Bore: 1.688 inch
• Venturi Size: 1.376 inch
• Warranty: Limited 90 Day

• This carburetor features a square bore flange bolt pattern, making it compatible with Holley, Edelbrock, Carter AFB, and Autolite style carburetors that have a 5 3/16" x 5 5/8" bolt pattern. If your intake manifold is of the spreadbore style, an adapter will be necessary for installation, similar to the Mr. Gasket #1932.