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ОглавлениеHOLLEY HISTORY, MODELS AND SERIAL NUMBERS
The 1950s saw the introduction of the Holley Series 4150 4-barrel on the 1957 Thunderbird. It was the beginning of the modular Holley 4-barrel, as we know it today. It was the first true performance carburetor and it became standard equipment on many high-performance automobiles.
The 1960s were huge for the hot rod industry and Holley; the 4150 became original equipment on many iconic Detroit factory muscle cars, powering such notable beasts as the popular Z28 Camaros, big-block Chevelles, Boss Mustangs, and Shelby Cobras. This era also saw the introduction of the Holley three-deuce multi-carb setups on 427 (Tri Power) Corvettes and 440 (Six Pack) Mopars. The now-famous Holley Double Pumper was also born in the 1960s. According to Holley, the now-world-renowned Dominator, which is a Double Pumper, was developed specifically for NASCAR racing and made its debut in 1969.
This carb (PN 1850) is an example from the 4160 series. It is a 4-barrel carb that has a single feed, a primary metering block with jets, one accelerator pump at the primary side, and a metering plate at the secondary side.
The 1970s saw Holley’s continued dominance in racing with nearly every factory NHRA Super Stock/Pro Stock racer running Holleys. That hasn’t changed; Holley carbs have powered more drag racers than all other carbs combined. This era also witnessed the introduction of Holley aluminum intake manifolds, including the once-popular Z-Series developed in conjunction with Zora Arkus-Duntov.
The 1980s marked Holley’s entrance into the fuel-injection market for which original-equipment EFI components and analog Pro-Jection retrofit fuel-injection systems for carbureted cars were introduced.
In the 1990s Holley continued its new product introductions. The wildly popular HP Pro series of race-ready carburetors was introduced and has become the standard in racing. SysteMAX engine kits were introduced with matched cylinder heads, intakes, and cams. Also in the 1990s, the Dominator evolved into the HP Dominator, huge billet electric fuel pumps were introduced, and retrofit EFI kits evolved into digital Pro-Jection 4D and 4Di.
Beginning in the 2000s, Holley introduced the popular Street Avenger, Truck Avenger, Street HP, and Ultra HP carburetors as well as billet mechanical fuel pumps and high-flow billet electric pumps. Although not covered in this book, Holley’s EFI systems have seen an enormous amount of change with the introduction of Avenger EFI, HP EFI, and Dominator EFI.
Two basic numbers are attributed to each Holley carburetor: the model/series number and the list/part number. The series number indicates the general type, or series; for instance, 4150, 4160, or 4500.
The 4150 series is the original 4-barrel modular design, which features metering blocks and replaceable jets on both the primary and secondary sides. The 4150 series is available with either mechanical or vacuum secondary operation.
The 4160 series is a slightly less-expensive variant of the 4150, featuring replaceable primary jets, but with a thin metering plate on the secondary side and no replaceable secondary jets.
The 4500 series is the Dominator big-CFM racing series, with a larger main body and a unique secondary actuation linkage design.
The model number is not stamped on the carburetor, but it’s easy to identify by simply examining the carburetor. If the secondary side has a metering block with jets, it’s a 4150; if not, it’s a 4160. The Dominator is easily identifiable by its size and the shape of the throttle bores.
For all practical purposes, the “list” number is the part number of the carburetor; it is the top number stamped on the carb. The list number is also stamped on the choke housing/air horn of all Holley carburetors that have a choke housing. Keep in mind that the Dominator series and some other race carbs, such as the Ultra HP series, do not have a choke housing; their list number is stamped on the top of the main body.
The list number (also called the part number) appears on the face of the choke housing on carbs that have chokes. The word “LIST” or the letter “L” sometimes precedes the part number; these were used randomly and have nothing to do with the year of manufacture.
As seen in this example (a 4160-series 600-cfm carb), 1850 is the part number. Following the part number is –2, which indicates that this is the 12th update or change for this carb; this likely means that the dies have been renewed 12 times. For models that have been produced for decades, dies and tooling wear and necessitate updates in the manufacturing process.
You don’t need to be concerned with the “dash” number. The bottom number is the build date. The first three numerals represent how many days from the start of a year that a carb was made, and the fourth numeral is the last digit of the year of manufacture. This carb was produced on the 133rd day of 1974, 1984, 1994, or 2004.
This carburetor’s choke housing is stamped 80670-3, which indicates that this is a 670-cfm Street Avenger. The number shown below the part number indicates that it was built on the 160th day of a year ending in 4. Based on when this carb was purchased, this likely means 2014.
This HP carb, because it has no choke housing, carries its identification on the side of the throttle body. It is clearly marked as a 4150. Note the “HP” designation under “4150.” Under the word LIST appears the list, or part, number of 82851, which indicates that it’s an 850-cfm Street HP carb. The build date of 0471 indicates that it was made on the 47th day of a year ending in 1. Based on when this carb was purchased, it was likely built in 2011.
Street HP carbs have a vibratory polished body as well as smoothly contoured venturi inlets. All Holley carbs can be easily identified; simply use the part number stamped on the carb and search the database on Holley’s website.
Carburetors such as the Dominator 4500 series do not have a choke housing, and as a result, the part number and date code are located on the side of the main throttle body.
This example shows a list number (also known as the part number) of 8082-3, indicating that it’s a 1,050-cfm HP unit for a single 4-barrel installation. Depending on design, Dominators are available designed for 1 × 4 (one 4-barrel carb) or 2 × 4 (two 4-barrel carbs for a dual setup) mounted to the intake manifold.
Although 4150- and 4160-series carbs do not display the model number, the Dominator identification does include the series number, which in this case is 4500. The build date indicates the 203rd day of a year ending in 4. Since this carb was recently purchased, I assume that it was built in 2004 or 2014.
The list number may be preceded by either the word “LIST” or by the letter “L.” The factory used the word “LIST” or the letter “L” randomly. Don’t worry about it. Some carbs have it and some don’t.
For example, a LIST 3310 is a 4150 series with either a 750- or 780-cfm rating, depending on when it was made. Another example is a Street Avenger carb’s choke housing/air horn stamped with the part number (e.g. 80670), without “LIST” or “L.”
A dash followed by a single- or double-digit number may be found immediately following the part number. This dash number simply indicates that a running change for that particular part number of carb had occurred (perhaps a die was changed, or other evolutionary production change). A –1 indicates the first running change. A –4 indicates the fourth running change, etc. From a selection/purchasing standpoint, you don’t need to be concerned with this number.
Located underneath the part number is a four-digit number, which indicates the build date. For instance, a build date might be 1954. This indicates that this particular carb was built on the 195th day of a year ending in “4” (which could mean 1974, 1984, 1994, or 2004).
Although this may seem confusing, dating a Holley carburetor is generally not too difficult. A date code should appear below the list number. Older carburetors have a three-digit code, while carbs made after 1972 used a four-digit code. You can always call Holley’s tech hotline and ask a Holley technician to help decipher the date code, but remember, this number doesn’t have any particular use for you, so you really don’t need to worry about it.
Series 4150 and 4160
Holley 4150s and 4160s are built on similar platforms with a few distinct differences. They both have square bores; the primary and secondary throttle bores are the same size, in a “square” configuration, in contrast to a spread-bore that has smaller primary and larger secondary bores.
The 4150 is a square-bore carb with center-hung floats and dual fuel feed inlets, and replaceable jets in both primary and secondary metering blocks. The 4150 carbs with vacuum-operated secondaries have an accelerator pump and a power valve on the primary bowl, but no accelerator pump or power valve on the secondary bowl.
The 4150 carbs with mechanical secondaries are known as Double Pumper carbs; they have the addition of a secondary accelerator pump, and depending on the specific part number, may also have a power valve on the secondary side.
The Series 4160 carbs also have a square-bore pattern but with more basic features. The primary side has a metering block with jets, but the secondary side has a thin metering plate with pre-sized orifices.
Although a metering block has replaceable jets for tuning purposes, a metering plate (used in the secondary side of 4160 carbs) requires changing the metering plate for secondary “jet” size tuning. Metering plates are available in a range of main-hole and idle-hole configurations. Secondary metering plates are secured to the main body with six 8-32 clutch-head screws, so you should obtain a 5/32-inch clutch-head driver for proper servicing during removal and installation.
A 4160 can be converted to a 4150 by adding a secondary metering block in place of the metering plate and swapping to center–hung-float fuel bowls. A 4150 can be converted to a 4160, although it is not a popular modification.
This side-by-side comparison of fuel-bowl styles makes them easy to identify. At the left is a 4160 (PN 1850) carb equipped with a side-hung float. At the right is a 4150 carb with a center-hung float. The 4150 carb has a metering block at the secondary side; the 4160 has a secondary metering plate. A 4160 is easily converted to the 4150 configuration.
4160 Details
This 4160 (PN 1850) carb has the metering block on the primary side (left) and no metering block at the secondary side (right). The secondary side includes a metering plate with no replaceable jets.
The 4160 carb has a single fuel inlet that accepts a slip-on fuel hose. This banjo-style fitting can easily be changed to a banjo fitting with a –6 AN threaded hose-end connection.
Because the 4160 carb has only a front/primary side fuel inlet, fuel is transferred to the rear bowl via this external fuel transfer tube.
Fuel bowls have either side-hung or center-hung floats. This is easy to identify by looking at the shape of the fuel bowl. If it is rectangular without a “V” protrusion on the casting, the bowl has a side-hung float, such as this example (PN 1850).
With the front bowl removed from this 4160-series carb, you can clearly see the jets near the bottom and the power valve at the lower center of the metering block.
When the primary fuel bowl is removed, you can see that the metering block is held to the body by the gasket. Small alignment dowels serve to center the block in place.
This fuel bowl, removed from a 4160-series carb (PN 1850) reveals a side-hung float, meaning that the float is hinged at one side. A side-hung float may be more susceptible to fuel-level changes during hard turns in contrast to a center-hung float that maintains fuel level better during turns.
With the front fuel bowl removed from this 4160 carb, the primary metering block is exposed; it is sandwiched between the body and bowl, and is gasketed on each side. The fuel bowl’s four screws secure both the metering block and bowl to the carb body.
Removing the secondary fuel bowl from this 4160 carb reveals a metering plate, which is secured to the body with six small flat-top screws.
The 4160-series carbs are easily converted to 4150 status: Remove the metering plate and its gasket and then install a metering block with the appropriate gasket and longer fuel-bowl screws.
The front and rear fuel bowls, front metering block, and rear metering plate on this 4160 carb have been removed. Note the external fuel transfer tube on this carb (PN 1850).
A metering plate provides a “fixed” secondary enrichment. A metering block allows fine-tuning with replaceable jets.
4150 Details
This is an example of a 4150 carb (PN 4779). It has 750 cfm, double-pumper operation with jet-equipped primary and secondary metering blocks and mechanical choke.
Holley Double Pumper carbs are available in various finishes, including this traditional chromate.
All 4150 carburetors have metering blocks at both the primary and the secondary sides.
All Double Pumper carbs include a dedicated accelerator pump for the rear secondary side.
Double Pumper carbs have fuel bowl level-checking ports. This carb (PN 4779) has the traditional brass-thread plugs that are removed to check fuel bowl level while adjusting float level.
Center-hung fuel bowl floats have needle and seat float adjustment. To make an adjustment, loosen the slotted plug (which is the lock), turn the hex to make the adjustment, and then tighten the lock.
This street Ultra HP has red billet anodized metering plates and baseplate.
Notice the “V” shape on this fuel bowl casting, which clearly indicates the use of a center-hung float.
Here, the primary fuel bowl has been removed on a 4150 to reveal the primary metering block.
Center-hung floats pivot at the upper center of the fuel bowl and are less susceptible to fuel-bowl level changes during hard-driving maneuvers.
The jets on the metering block thread in at the front side; the power-valve threads in from the rear of the block. The power valve is rated at a specific vacuum, in inches of mercury. They are usually found only on the primary side but are also installed on the secondary metering block of certain high-performance models.
This is part of the fuel enrichment circuit that opens gradually to full open, depending on engine vacuum. During cruising, the valve is shut. As engine-load demand increases upon acceleration, engine vacuum begins to drop, allowing the power valve to open. Power valves are available in a range of vacuum ratings, which allows you to tailor it according to your needs.
A Holley power valve includes a four-sided head that can be serviced with a 1-inch wrench, but the flats are fairly thin. A dedicated power-valve wrench is highly recommended.
This white plastic piece is commonly referred to as a “whistle.” It aids in preventing fuel from spilling out of the primary vent tube during hard accelerations. They are featured on some carbs but are added easily to those without them.
The primary and secondary fuel bowls and metering blocks have been removed on this typical 4150-series carb. This is a 750-cfm Double Pumper (PN 4779).
4150/4160 Interchangeability
Parts that are interchangeable between the 4150 and 4160 series include jets, power valves, floats, needle/seat assemblies, vacuum diaphragm springs (for those equipped with vacuum secondaries), fuel bowl vent components, some accelerator pump hardware, primary bowl gaskets, and, of course, carb-to-manifold gaskets.
Double Pumper
If a 4150 carb has mechanical secondary operation, it has both a primary and secondary accelerator pump, and is referred to as a Double Pumper carb. Depending on the model, 4-barrel carburetors have either vacuum-operated secondaries or mechanical secondaries.
All primary sides include an accelerator pump, which is activated by the throttle linkage. The pump serves to inject an added boost of fuel to eliminate bog or lag when the throttles are opened, which is especially critical at lower engine speeds.
With a vacuum secondary design, the secondaries begin to open according to vacuum developed in one of the primary bore venturis, as engine load increases. During quick accelerator operation under load, a slight delay may be encountered while the secondaries begin to open. You can tune the vacuum secondary by changing to a lighter or heavier spring inside the vacuum diaphragm housing.
Double Pumper carburetors are equipped with mechanical secondaries; a second, separate accelerator pump circuit is located on the secondary side. The secondaries receive an immediate shot of initial fuel from the secondary’s accelerator pump as the throttle linkage progresses.
The 650-cfm 4150 (PN 76650BL) is one of Holley’s Double Pumper Ultra series, featuring billet aluminum metering blocks and a billet aluminum baseplate. The Ultra series is available with various color-coded blocks and baseplate in blue, red, and Hard Core Black.
The Ultra Series 4150 carbs are offered in either mechanical- or electric-choke versions. The Ultra HP series eliminates the choke provision.
Double Pumper carbs are best suited to lighter-weight vehicles, those equipped with a manual transmission, and those with high–stall-speed automatic transmissions in the 3,000-rpm range.
Avenger
Introduced In 2009, the HP-series Street Avenger includes cast aluminum bodies with billet metering blocks and baseplates that reduce overall weight by an astounding 5 pounds compared to previous 4150 carbs. This line of carbs is also offered in both diecast and aluminum body construction. The Ultra Avenger series offers some appearance enhancements such as metering blocks and bodies in Hard Core Black, Hard Core Gray, blue, and red. The lineup is quite extensive.
In 2011, Holley released a new aluminum Ultra HP 4150-series carb with 30 new and improved features, including larger 1.6-inch venturis. The Avenger series is offered in ratings from 470 to 870 cfm, in both street and truck/off-road configurations. Although the majority of Avenger carbs have electric choke, six versions within the entire lineup are offered with manual choke. All Avengers have vacuum secondaries.
Street Avenger carbs were designed and calibrated specifically for optimal street performance, with features including a secondary metering block, four vacuum ports (for positive crankcase ventilation, power brake, spark, and vacuum accessories). The Avenger series is not designed for immediate bolt-on use with Chrysler automatic overdrive transmissions. If used with a GM overdrive TH700R4 or TH200R4 transmission, you need Holley’s transmission kickdown cable bracket (PN 20-95) and geometry corrector (PN 20-121). Depending on your throttle bracket, you also need a throttle stud (PN 20-2, 20-38, or 20-40). The Street Avenger includes a Ford automatic transmission kick-down, but not for use with overdrive transmissions.
The Ultra Street Avenger series has aluminum construction and anodized billet aluminum metering blocks and baseplate (available in various colors). The Ultra is lighter (for those concerned with minimizing weight) and comes in several anodized colors. Personally, I love the Ultra series; in addition to the benefit of reduced weight, they look way cool.
In addition to reduced weight and the obvious visual appeal, the anodizing protects the aluminum from long-term corrosion.
The Ultra Series 4150 carbs has convenient glass fuel bowl sights, making it much easier to check fuel bowl level during adjustments without the need to remove a solid brass plug.
In recent years, black has become the go-to color for those who wish to break out of the chrome-and-color mold and create a pro, understated, somewhat monochromatic appearance. Holley’s Hard Core Black finish has become very popular. This is a 750-cfm Ultra Double Pumper (PN 76750HB).
In the Ultra series, the two letters at the end of the part number indicate color (HB is Hard Core Black, RD is red, BL is blue, etc.).
Holley Ultra 4150 street/strip Double Pumper carbs share the same features, including aluminum construction for reduced weight, billet aluminum metering blocks and baseplate, mechanical secondary operation, choice of manual or electric choke, four-corner idle adjustment, clear sight windows on both bowls, are optimized for out-of-the-box street/strip calibration, and are available in 650 to 750 cfm.
All Ultra and Ultra HP carbs have double-pumper operation with an accelerator pump for each fuel bowl.
The Ultra HP series Double Pumper carbs have no choke and are designed for racing applications for which a choke is not required. This is a tumble-polished aluminum body and billet aluminum metering blocks and baseplate anodized in red (PN 80801RD).
The Street HP carbs have a smooth, contoured venturi area for superior airflow. The boosters, the dichromate finished components directly over each venturi, are the down-leg style with a single fuel hole inside each barrel opening.
The Street HP series is essentially a 4150 race carb, using features taken from race HP and Double Pumper carbs, and then “tamed and tuned” for street and light-competition applications. The Street HP series is offered in yellow chromate, black, or tumble-polished finish. Sizes range from 600 to 950 cfm. The metering system includes a timed-spark port for a vacuum-advance distributor and it is calibrated for superior throttle response for street/strip use. The Street HP baseplate offers several vacuum ports for power brakes, positive crankcase ventilation (PCV), etc.
Although various finishes/colors are offered in Holley’s current lineup, Hard Core Black (often referred to as Hard Core Gray) has become increasingly popular for those who wish to deviate from bright colors. This Ultra HP carb is mounted to an intake manifold that has been smoothed and hydro-dipped for a carbon-fiber appearance.
Street Avenger carbs are specially designed and calibrated for optimum street performance; they are available in sizes ranging from 570 to 870 cfm. All have vacuum secondary operation and are available with either manual or electric chokes. The aluminum construction reduces weight.
Note the dual fuel-feed fittings on the primary and secondary bowls. However, the Avenger is not a double-pumper carb, so don’t assume that a carb is a Double Pumper just because it has center-hung fuel bowls and dual feed.
Note the absence of a secondary accelerator pump on the rear bowl on this Street Avenger. Remember, just because a carb has a dual feed fuel fitting for each bowl, it’s not a Double Pumper unless it has an accelerator pump on each bowl.
Avenger carbs have an accelerator pump only at the primary bowl location.
Avengers are 4150-series carbs, so the secondary side has metering blocks with serviceable jets.
A quick-change vacuum housing cover allows changing the vacuum spring without the need to disassemble the entire housing unit. The cover is secured with two screws. Simply remove the two screws and then remove the cover and spring. Some carbs, such as the Avenger, have this as standard equipment.
The quick-change feature can be retrofitted to other carbs with a secondary vacuum kit. The housing cover and spring simply pull out. An O-ring seats onto the top of the housing. If it pops loose, be sure to reinstall it into its groove. The vacuum diaphragm spring sticks onto the housing top and is easily changed to a lighter or heavier spring to tune the secondary opening rate.
For off-road truck applications where severe vehicle operating angles are routinely encountered, Holley’s Truck Avenger carb has a main vent tube that connects both primary- and secondary-side main vents. This prevents excess fuel spillover from sloshing out of the vent tubes. This is a 670-cfm Truck Avenger (PN 90670). (Photo Courtesy Holley Performance Products)
The Avenger Truck series is a unique design, intended specifically for truck and off-road applications. It has a single fuel inlet, square fuel bowls with side-hung floats, and an exclusive metering block and vent tube designed to prevent fuel spillover at extreme angles. Flood-free operation accommodates climbing angles up to 40 degrees as well as side-hill maneuvers and nose-down descents up to 30 degrees.
Dominator
The “big boy” of Holley carburetors is the venerable Holley Dominator series, known as the 4500 series; it is often referred to as the “elephant” carb. The Dominator was designed as a large-airflow racing carburetor and debuted in 1969 (although some sources say 1968), initially to address the needs of NASCAR competition. Shortly thereafter, it was offered to the public. Today, the 4500 is extremely popular in drag racing applications. Versions are offered in 1,050, 1,150, and 1,250 cfm, as well as a “street” version rated at 750 cfm that was introduced basically to satisfy hobbyists who hungered for the Dominator look.
The Dominator flange is unique to the 4500 series. You must use a manifold designed for use with a Dominator or install an adapter mounting plate to accept a Dominator. A Dominator cannot bolt to an intake manifold that is not designed for its larger bolt pattern.
The Dominator is often referred to as the “elephant” carb because of its large footprint and its large range of CFM ratings. The Dominator 4500 series ranges from 750 cfm all the way to 1,475 cfm.
Float bowls and metering blocks are similar to those found in the 4150 series, but the 4500 features an appreciably larger main body with the unique secondary linkage located between the front and rear throttle bores, underneath the main body. Throttle bores have a hefty 2.00-inch diameter, compared to 4150/4160 diameters that generally range from 1.563 to 1.688 inches.
The Dominator series was developed specifically for top-end horsepower and torque. The classic Dominator has an aluminum main body with contoured venturi inlets for balanced airflow, a high-flow metering system, and annular boosters. The fuel bowls allow inlet plumbing on either side. The classic Dominator is offered in two- or three-circuit configurations and choices of 1 × 4 or 2 × 4 setups.
The new Gen 3 Dominator line represents an evolution in Dominator design with a 5/16-inch–taller main body that allows larger-radius air entries and fully machined venturi surfaces. It also includes 20 percent larger fuel bowls to eliminate starvation, 12-hole billet booster inserts, adjustable external linkage, and provisions for mounting a throttle position sensor. Annular boosters on the Dominator have a series of fuel orifices spaced around the inside diameter of each booster for superior fuel atomization. Boosters help to pull fuel from the bowls as air passes through them.
The Dominator 4500 has a non-staggered, square bolt-hole pattern. Other 4-barrel models have a staggered pattern with the bolt holes spaced farther apart from front to rear when compared to left-to-right bolt holes.
Throttle bore diameters on 4150- and 4160-series carbs measure 1.563 to 1.688 inches, depending on specific part number.
The throttle bore diameter on Dominator (4500-series) carbs measures 2.00 inches.
You don’t need a tape measure to readily see the difference in throttle bore diameters. The Avenger (left) has 1.688-inch bores, while the 1050 Dominator (right) is gifted with whopping 2.00-inch bores. Bore diameters are even larger on high-volume models, with 1,475-cfm Dominators featuring 2.350-inch bores.
All Holley 4-barrel carburetors (except for the 4500 series) have a baseplate bolt pattern with the baseplate-to-intake manifold bolt holes stagger-spaced 5 (left to right) × 5⅝ inches (front to rear). As previously mentioned, the 4500-series Dominator baseplate bolt pattern is unique to that series and includes a square bolt pattern measuring 5.375 × 5.375 inches. The Dominator requires the use of an intake manifold designed to accept a Dominator. However, adapters are available that allow you to mount a 4150/4160 to a Dominator manifold and vice versa. Depending on the specific intake manifold, installing a Dominator onto a manifold designed for the 4150/4160 carbs may require enlarging the manifold’s plenum ports.
Holley Carburetor Models and Types
Holley carburetors are available in different “series” designs. Within each family are variations in CFM, choke design, secondary design (on 4-barrel carbs), etc.
The 4160-, 4150-, and 4500-series carburetors are, by far, the most commonly used. Depending on the engine size and application, carbs in these three series can be applied to street vehicles. However, generally speaking, the 4160 is intended for the street, the 4150 is for serious street and racing, and the 4500 is designed primarily for racing.
For a complete listing of specific Holley carburetor models and the vehicles on which they were installed, please refer to the Appendix.
Series 4160
The 4160 includes a single fuel inlet with a transfer tube that feeds the vacuum-operated secondaries and a secondary metering plate rather than a secondary metering block. The metering plate is non-adjustable and has no replaceable jets. A power valve and an accelerator pump are located on the primary side only. The 4160 carburetors are the less-expensive versions of the 4150s but can be upgraded easily to 4150 status by installing a secondary bowl and metering block kit.
Series 4150
The 4150 carburetors are similar to 4160 carbs; their primary difference lies with secondary operation. The 4150 is enhanced with features such as dual fuel inlets, vacuum or mechanical secondary operation, metering blocks (with replaceable jets) on both the primary and secondary sides, and a power valve on both the primary and secondary sides. The 4150 series offers a much wider range of CFM sizes compared to the more “basic” 4160.
Series 4500
Famously known as the “Dominator” series, the 4500 is the big boy on the block. Notable differences between the 4150 series and the 4500 series are the larger 2.00-inch bores, a secondary throttle linkage that runs internally, throttle-shaft openings sealed to prevent contamination, and the elimination of an air horn/air choke to control air entry. The Dominator series has a larger bolt pattern for intake manifold mounting. Although adapters are available to mount a 4500 carb onto a 4150 intake manifold, the proper choice is a manifold that is designed to operate with a 4500-series carburetor. Dominators are good choices for engines producing more than 625 hp.
Series 4165
This series is known as a Double Pumper because it features mechanical secondaries, an accelerator pump at both bowls, and a metering block with jets at both primary and secondary sides. It has a square bore pattern.
Series 4175
These carburetors have a spread-bore base and are designed as a direct replacement for the GM Quadrajet. Series 4175 carbs have electric chokes and a single fuel inlet.
Series 4010
These carbs have a square bore with either mechanical or vacuum secondaries.
Series 4011
This series is essentially the same as a 4010, but is designed for spread-bore intake manifolds. It is offered with either mechanical or vacuum secondary operation.
Series 4224
Built as a 660-cfm drag racing carb, this carb has a center-squirter design that squirts fuel into all four barrels at the same time, aided by a hefty 50-cc accelerator pump.
The 4150 and 4160 bolt spacing, from front to rear measures 5⅝ inches.
Dominator bolt spacing, from left to right, is specified at 5⅝ inches.
Dominator bolt spacing, from front to rear, is specified at 5⅝ inches.
The 4150/4160 series requires a 5⅛-inch air cleaner/gasket; the larger Dominator requires a 7-inch air cleaner and gasket. These are the standardized published sizes that appear in all catalogs; they provide a comfortable drop-on fit. Actually, the 4150/4160 carb air cleaner inside-diameter gasket surface measures approximately 5.001 inches; the inside-diameter gasket surface of the Dominator measures approximately 7.251 inches.
Air Cleaner Threads
Most Holley carbs, including the 4150/4160 series, have a 1/4-20 threaded center hole to accept an air cleaner stud. The Dominator (4500) series has a larger 5/16-18 threaded hole. Inexpensive male/female adapters are readily available from any performance retailer to allow the use of either stud size. Adapters are available with 1/4-20 male thread and 5/16-18 female thread as well as 5/16-18 male thread and 1/4-20 female thread.
