750CFM Ultra XP Marine Carburetor

Mechanical Secondary

Billet Color

PART# 0-80803HBM

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Xtreme Performance - Holley Ultra XP™ Marine carburetors! Ultra XP Marine carbs are up to 38% lighter than our traditional race carbs, have fuel capacity that is 20% greater and other new features! They’re available in Hard Core Gray™ hard coat anodized finish with Black™ billet for improved corrosion protection from corrosion in fresh water or salt water conditions. Holley Ultra Marine XP carburetors offer new features such as an integrated idle bypass valve that allows for idle adjustments while maintaining the correct throttle plate to transfer slot relationship, high capacity fuel bowls which feature 20% more fuel capacity to eliminate starvation, integrated fuel shelf to minimize fuel aeration and internal baffling to control fuel slosh. Other features include all aluminum construction, fully tunable billet metering blocks, billet base plate, adjustable secondary linkage and knurled (hand adjustable) curb idle screws. The new Ultra XP Marine models are built to exceed the Coast Guard standards and are J1223 Marine Standard certified. So, if you are hitting the lake for an easy cruise or some high speed fun, these new performance carburetors will meet and exceed your performance demands!


  • Aluminum Construction (saves 4.5 lbs - 38% weight savings)
  • Hard Core Gray with black anodized billet aluminum metering block and booster inserts
  • Contoured venturri inlet offers balanced airflow for increased horsepower
  • Air bleeds moved outward to allow a smoother transition of airflow from the top of the carburetor into the venturii
  • Metering blocks feature improved durability, true gasket sealing and fully adjustable (emulsion bleeds, power valve channel restrictors & idle feed restrictors)
  • 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. Helps maintain good idle control when using radical camshafts.
  • Dual 30cc accelerator pumps provide the perfect amount of fuel from idle to full throttle
  • Fuel bowls provide 20% more fuel capacity while controlling slosh with internal baffling
  • Clear sight windows on both sides of bowls for easy and safe fuel level adjustments
  • Built in drain plug in front center of bowl provides easy access to empty contents of bowl
  • 8AN (o-ringed) inlet threads offer a large variety of plumbing options and can be plumbed from either side
  • 4 corner idle allows you to precisely control your idle system
  • Elongated (dual pattern) mounting holes allow fitment on intakes with square flange (Holley 4150™ style) or large flange (Holley Dominator® style)
  • Knurled (hand adjustable) primary and secondary curb idle screws allow for easy idle adjustment without the use of tools
  • Primary throttle shaft capped to prevent entry of debris & contaminates
  • Stainless steel adjustable secondary link. Provides choice of 1:1 or progressivesecondary throttle actuation for ultimate control of secondary opening rate
  • Baseplate designed with a boss that can be consumer machined for vacuum source
  • Includes notched float and jet extensions
  • 100% wet-flow tested by Holley technicians to assure it arrives ready to run!


Billet ColorHard Core Gray with Black
BoosterDown Leg
Emission Code3
FinishHard Core Gray
Fuel InletDual
Primary Main Jet76
Primary Power Valve6.5
Primary Pump Nozzle Size31
Product TypeCarburetor
Secondary Main Jet76
Secondary Power Valve6.5
Secondary Pump Nozzle Size31
Supercharged ApplicationNo
Throttle Bore1.688 inch
Venturii Size1.376 inch
Part Number0-80803HBM

Service Parts


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.

*Free Shipping & Handling only offered to the contiguous US on orders over $100.

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