Holley HP™ Carburetors have been the standard in racing Carburetors for nearly two decades. So how do you make them better? You make them 38% lighter, increase the fuel capacity by 20% and add 30 other new features! They're available in the all–new Hard Core Gray™ hard coat anodized finish with Black™ billet for superior corrosion protection.

100% Holley – Made in the U.S.A.
97% aluminum construction
38% weight savings
20% more fuel bowl capacity
10 new fuel bowl features
10 new base plate features
new metering block features
new main–body features
new carburetor...Ultra HP

Features

American Made - Materials and Assembly
Aluminum Construction (saves 4.5 lbs - 38% weight savings)
Available in Hard Core Gray or Black Anodized Finish.
Available in 600, 650, 750, 850 and True 950 CFM
Available tumble polished with Red™ or Black™ billet.

6061T6 BILLET ALUMINUM METERING BLOCKS

Improved durability, true gasket sealing (sealing surface integrity), bright dipped anodized for good looks and corrosion protection
Fully adjustable (emulsion bleeds, power valve channel restrictors & idle feed restrictors). Power valve channel restrictors now machined lower in metering block for improved fuel delivery to power valve circuit
Accelerator pump channel now internally drilled eliminating need for external plug
Excess material removed for improved fuel capacity
Integrated pry-point assists in disassembly from fuel bowl and mainbody preventing damage to gaskets and gasket surfaces
New snap in place bowl vent whistle makes removal and/or replacement easier

6061T6 BILLET ALUMINUM BASE PLATES

Improved durability, true gasket sealing, bright dipped anodized for good looks and corrosion protection
Elongated (dual pattern) mounting holes allow fitment on intakes with square flange (Holley 4150™ style) or large flange (Holley 4500™ Dominator® style)
Dedicated race-only throttle lever with all unnecessary street attachment points & tangs removed
Stainless steel adjustable secondary link. Provides choice of 1:1 or progressive secondary throttle actuation for ultimate control of secondary opening rate
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
Factory machined accessory mounting hole for easy addition of adjustable throttle stop
Throttle body and new secondary pump cam lever designed to provide positive throttle stop on secondary side. Delivers safe & reliable 90° opening and return of throttle plates while ensuring maximum airflow
Baseplate designed with a boss that can be consumer machined for vacuum source

ALL NEW FUEL BOWL DESIGN

Completely redesigned from the ground up for racing
20% more fuel capacity vs. a traditional v-bowl eliminates fuel starvation and provides consistent air/fuel ratios
Internal baffling to help control fuel slosh and minimize float level fluctuations in hard launching or cornering situations
Fuel shelf below the needle and seat to greatly minimize fuel aeration and promote more consistent metering
Fuel trough designed into floor of bowl to route fuel flow directly to the jets and assist in keeping jets covered by fuel
Clear Pyrex® 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
Contoured entry provides smooth fuel flow directly to needle & seat
-8AN (o-ringed) inlet threads offer a large variety of plumbing options (come standard with -8AN o-ring to -6AN male adapter and -8AN plug). Can be plumbed from either side
Material added in key areas (needle & seat area, fuel inlet, sight window area) for added strength in the demanding race environment
Note: New lengthened fuel line required due to increased length of bowls (see Holley p/n 34-42, 34-43, 34-44 or Earl’s p/n AT104195ERL, AT104295ERL & AT104286ERL)

UPDATED MAIN BODY DESIGN

Air bleeds moved outward to allow a smoother transition of airflow from the top of the carburetor into the venturii
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.
All unnecessary mounting bosses removed for a smoother, cleaner appearance
Contoured hex head squirter screws for streamlined airflow
Cast in Holley HP logo for easy identification by race sanctioning bodies
Available in all new Hard Core Gray™ hard coat anodized with Black™ billet. First-ever hard coat anodizing on fuel bowls and mainbody - actually penetrates the aluminum for superior corrosion protection.
Adjustable Throttle Stop bracket and WOT Microswitch brackets available
Due to hard coat anodizing process on cast aluminum, some color variation may be visible on Hard Core Gray™ carbs.

ORIGINAL HP FEATURES