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Repair vs Performance Parts | Intake Manifolds & Carburetors

We examine how intake manifolds and carburetors contribute to air & fuel flow into your engine, and whether "replacement" (OE style) or "performance" (aftermarket) versions of each may be best for you.
Repair vs Performance Parts | Intake Manifolds & Carburetors

In this guide, we'll look at role intake manifolds and carburetors play as part of your vehicle's air intake system, and examine how "replacement" (OE factory style) and "performance" (aftermarket) versions of each of these products differ, along with advantages of each. Our goal is to help you understand when there's a need to replace malfunctioning components, and why you may wish to indulge the want for components that ring in better performance.

What Is An Intake Manifold?

Intake Manifold On V-Shaped Engine
Intake manifolds on V-shaped engines are typically mounted on top of the engine between both cylinder banks.

An intake manifold is an integrated assembly that sits atop the engine, consisting of a series of tubes which distribute air drawn from outside the vehicle to each cylinder. On V-shaped engine blocks, an intake manifold typically sits between the two cylinder banks (secured to both) while inline engines feature a manifold bolted onto the side of the cylinder head.

Side Intake Manifold For Inline Engine
Intake manifolds for inline engines are often mounted on the side of the engine, as seen in this diagram.

You can learn more about intake manifolds by reading one or both of these articles on our site. The article " How Does An Internal Combustion Engine Work?" contains a section about the intake manifold; and " Why Does My Car Have a Plastic Intake Manifold?" explains the manifold material choices in some detail.

Carburetors, Thermostats, Throttle Body Assemblies, Fuel Injectors
Intake manifolds typically serve as a mounting point for carburetors, thermostats, throttle body assemblies, fuel injectors, and more. If you're changing your intake manifold, this is an excellent time to replace these items with new ones during the process. We can help with that, also.

Intake manifolds serve as a mounting point for carburetors, thermostats, throttle body assemblies, fuel injectors, and more depending on vehicle manufacturer engineering preferences. Installing a replacement manifold is the perfect time to replace any of those items with new ones, since the old ones would need to be transferred over to the new manifold anyway.

To create tight seals where the intake manifold bolts to the cylinder head, and when any halves are joined together, special gaskets are used. External items bolted to the intake manifold such as throttle bodies or carburetors use similar gaskets as well.

Intake Manifolds Gaskets Seals
Intake manifolds we sell typically include all gaskets and seals necessary for installation on your specific engine.

Intake manifolds we sell typically include gaskets and seals necessary for installation. Naturally, the integrity of all seals is critical in order to prevent air leaks which can cause a lean air/fuel mixture, rough idle, and poor performance.

How To Recognize a Faulty Intake Manifold

When manifolds go bad, an air leak is created - either through faulty gaskets that may be crumbling, or because of a manifold assembly that's become warped or cracked over time (it happens).

Reduced engine power and sluggishness may result, but the best way to be sure a manifold is bad is to listen to the engine closely when it's idling. If there's a leak, you'll hear it. The noise may resemble a whistling, hissing, slurping, or sucking sound - but it will definitely be air squeezing through something. Spray small amounts of starting fluid around the manifold seals when the engine is idling. If engine speed changes as a result of the spray slipping into the manifold, then you've found the source of the leak.

The engine may also idle roughly or stall at low rpms, and it may continue to hiccup for a little bit on its own after the ignition is switched off. Or, if the intake manifold features a "valley pan" channel for coolant to run through, you'll see a visible leak if the seal is the problem.

Intake Manifolds - Replacement

We sell all types of OE style replacement intake manifolds for a range of vehicles dating back decades, from a variety of continents. But whatever car or truck you have - order a replacement manifold through us, and you'll get parts that match the contours, shapes, thicknesses, strengths, and durability of OE components. And, very importantly, they will match the original materials used (unless otherwise noted). Many of the replacement intake manifolds we sell feature design improvements that eliminate known failure points of originals.

OE Style Replacement Intake Manifold Vs Improved Replacement OE-Style Version With Aluminum Reinforcements
Shown from left to right are an original Ford 4.6 V8 factory plastic intake manifold, and an improved Replacement OE-style version with aluminum reinforcements, improved plastic composites, better seals, and heavier-duty construction overall. This is just one example of Replacement intake manifolds we sell with design improvements that eliminate known OE failure points.

Replacement Intake Manifolds We Offer

Original plastic intake manifolds used on 1990s General Motors 3.8-liter V6s, Ford 4.6-liter V8s, and Chrysler 4.7-liter V8s are among the more common examples of designs prone to early failure. For these engines, check out the Dorman Intake Manifold and ATP Intake Manifold. The Mopar Intake Manifold is available for a wide variety of engines found in Chrysler, Dodge, Jeep, and Plymouth vehicles originally equipped with plastic intake manifolds.

Dorman Intake Manifold Versions
Different versions of the Dorman Intake Manifold.

We've got the AC Delco GM Original Equipment Intake Manifold covering all GM brands from 1993 on (including Hummer, Saab, Saturn, and select Suzuki vehicles). And if you've got a European or Asian import, take a look at the Genuine Intake Manifold.

Intake Manifolds - Performance

A performance intake manifold is one of the best ways to help your engine breathe better and create more power - especially if you've added a supercharger or turbocharger. But you don't need major engine modifications to benefit from an upgraded intake manifold. This is because modern OE manifolds are essentially compromised to meet cost targets and underhood clearances. They're also designed to work with OE levels of tune, a factor that translates to narrower runners in order to keep air velocities high at low rpms.

Regardless of how (or if) you've modified your engine, the greater airflow ability of a performance intake manifold will provide a shot in the arm. And whether you have a 4-, 6-, or 8-cylinder engine created for high revs or low-end torque, we've got manifolds tailored to each specific motor with advanced designs that allow more air to pass through them. What's even better is that additional air passing through is also less restricted thanks to wider runner tubes with smoother bends and contours.

But back to engines that have been modified for more power. These mills desperately need a greater volume of air, and a performance manifold will help deliver exactly that. Factory designs aren't going to cut it if you've swapped in new camshafts and cylinder heads, or if you've added a more capable carburetor or injectors that can process a higher flow rate of fuel. Other modifications that can see additional gains are exhaust headers, performance throttle bodies & MAF sensors, cold air intakes, custom exhaust systems, and electronic tuners that remap spark timing and fuel delivery.

Many performance intake manifolds we sell are equipped with additional ports that can be used for nitrous injection, gauges, or testing probes. Plus, you'll find a wealth of related components on our site such as gaskets, mounting bolt kits, adapter plates, spacers, sensors, and more.

Aluminum Construction Saves A Great Deal of Weight

An original equipment intake manifold made of cast iron can be quite large and heavy - especially on V- engines. Switching over to a performance intake manifold made of aluminum is an easy way to make the vehicle lighter in the front by a significant amount.

Crossover Tubes Inside Intake Manifolds

Some older OE intake manifolds may be equipped with "heat crossover tubes", which essentially hold more hot air inside the intake manifold for the purposes of quicker engine warmups and lower emissions. In most cases, such crossover tubes have been phased out as electronic fuel injection and secondary air pumps solved these problems much more efficiently.

Trapped heat in crossover tubes can cause "vapor lock" conditions on carburetors when the engine is first shut off. This is because fuel still sitting in the carburetor can bubble up, boil, and become aerated due to this extra heat. Until the fuel cools down to full liquid form, it can be difficult or impossible to restart the engine.

Performance intake manifolds typically do not include heat crossover tubes. So if your OE manifold does have one, it may not be suited to engine modifications. Plus, an air/fuel mixture with cooler, denser air creates more power across the board.

As we mentioned earlier, we offer performance intake manifolds tailored to each engine layout. If you've got an inline 4-cylinder, we've got high-velocity large runner intake manifolds that boost high rpm horsepower. If you've got a V8 engine, we've also got 4-barrel intakes that maximize power from idle to 5500 rpm, as well as manifolds for higher revs.

Curved Performance Intake Manifold
Some performance intake manifolds such as this one feature a more curved shape. This is to create a higher amount of airflow that's also smoother, without turbulence and dead air zones caused by sharp bends.

To view recommended manifolds available for your specific car or truck, just enter the year, make, and model in the "Select Vehicle" drop boxes at the top of the screen.

Intakes Designed For Carburetors

For hot rodders who appreciate the looks and performance of multiple carburetors, we offer dual quad and tri-power setups, and single and dual quad tunnel rams.

You may also consider a manifold and carburetor kit (many are available with satin or chrome-like finishes) with components custom-engineered to work together for maximum performance. With such kits, you'll get all gaskets, bolts, and related hardware needed to ease installation.

Classic Muscle Car Intake Manifold Set For Three 2-Barrel Carburetors
Shown here is a classic muscle car intake manifold set up for three 2-barrel carburetors.

Intake manifolds designed to use multiple carburetor setups for more power will most commonly use three 2-barrel carbs, or two 4-barrel carbs. To name a couple of examples, we've got the Edelbrock Six-Pack Dual Intake Manifold (three 2-barrels) and the Edelbrock RPM Dual Quad Intake Manifold & Carburetor Kit (two 4-barrels) which includes the intake manifold plus two tailored carburetors.

Edelbrock Six-Pack Dual Intake Manifold
The Edelbrock Six-Pack Dual Intake Manifold is an example of a setup with two 4-barrel carburetors.

High Ram Intake Tops

For select vehicles, we also offer "high ram" sections designed to draw in larger amounts of air thanks to long plenum tubes. When these work together with increased fuel delivery, they can effectively boost torque and even high-end horsepower. Typically, these are not legal for street use (individual pages will confirm this) - but they are well-suited to drag race, marine, off-roading, truck pulls, and other track applications.

High Ram Intake Tops

High rams are also a natural fit for fabricators of custom induction systems. Often, the base area is designed with a modular configuration that can accept a number of fuel-injection and carburetor setups. Because of their increased height, high rams won't fit under stock hood panels - so you'll need to cut a hole in the hood for a custom air scoop.

To check if these are available for your vehicle, we recommend entering year, make, model, and engine information in our drop-down boxes along the top of the screen.

Carburetors - How They Work

Holley Special Emissions Stock Replacement Carburetor
The Holley Special Emissions Stock Replacement Carburetor.

Now, let's look at carburetors. A carburetor is an assembly which sits on top of the engine intake manifold that combines vaporized fuel and air to form a combustible mixture that can be burned in an engine's cylinders. The carburetor changes the quantity of fuel and air in response to varying conditions such as starting, idling, cruising, and full power.

Examples Of 1-Barrel, 2-Barrel, 4-Barrel Carburetors
Shown from left to right here are examples of 1-barrel, 2-barrel, and 4-barrel carburetors.

In use since the earliest days of the automobile in various forms, carburetors have been phased on out vehicles built in the last several decades - replaced by electronic fuel injection throttle bodies which have cleaner emissions and are more efficient.

Inside Carburetor Basic View
Shown here is a basic view within each barrel inside a carburetor.

You can read more about the basic functions of a carburetor by accessing the text you'll find near the bottom of our Replacement Carburetors home page. The illustration below is provided so that you can identify some of a carburetor's major components.

Carburetor Major Components Scheme

Below, we'll discuss a few of the replacement and performance carburetors we offer. Whichever you decide on, you'll also find we've got a great selection of individual parts such as choke cables, accelerator pedal connection cables, throttle diaphragms, and return springs along with various bushings, ball joints, and other hardware. Check boxes along the left side of the screen will make it easy to narrow your search for any of these items.

Carburetors - Replacement

If you're satisfied with your vehicle's stock performance, fuel economy, and general on-demand responsiveness, our replacement carburetors will match or exceed the quality and durability of your OE one at excellent prices. We know full well just how complex carburetors can be, so we go to great lengths to ensure replacement OE ones we sell are sourced from manufacturers with proven track records of quality, durability and performance.

OMIX-ADA replacement Carburetor
The OMIX-ADA replacement Carburetor.

For a wide range of vehicles dating back decades, we've got the Tomco Remanufactured Carburetor. These are actual, original factory OE carburetors that have been taken apart and rebuilt using new components that restore their appearance, function, and reliability to like-new levels.

Tomco Remanufactured Carburetor
The Tomco Remanufactured Carburetor.

For remanufactured carburetors, you'll see a "core deposit" noted on the product page. A core deposit refers to an additional charge that is paid upfront upon purchasing an item. Once you receive your rebuilt carb and install it, simply return your old carburetor directly to the product manufacturer. Once they receive it, you will be credited your core charge. In a sense, they're buying your old carburetor from you in order to refurbish it for the next customer. Specific instructions regarding how to get your core deposit refund can be found here on our website.

Most of our OE style replacement carburetors are offered for more specialized applications. To name a few, we've got the Crown Carburetor (older Jeep models dating back to the 1940s), OMIX-Ada Carburetors (1946-90 Jeep models including Carter style carb designs), Holley Specialty Emissions Classic Holley Replacement Carburetor (1960s GM performance models), Holley Specialty OE Muscle Car 2 Barrel Carburetor (classic Mopar muscle cars), and Redline Carburetor Kit (1980s Isuzu models).

Carburetors - Performance

While electronic fuel injection provides better fuel economy and lower emissions than a carburetor, it has no absolute advantage in the arena of power. For example, just look at the huge gobs of power produced by carbureted engines used in serious racecars.

What we're saying is - in order to get more power, you don't have to deal with the expense and complication of converting your factory intake from a carbureted setup to one with electronic fuel injection. We can supply you with larger and more performance-oriented carburetors that will give you the increased fuel capacity you need for the power you crave.

Performance Carburetor With Typical Adjustments
An example of a Performance carburetor, and typical adjustments found on many of them.

We have lots of details about performance carburetors, CFM (cubic feet per minute) air flow, primaries and secondaries, and multiple carb setups, all in the text near the bottom of our Performance Carburetor home page. Take a look there and educate yourself a bit as you begin to peruse your choices. The photo below is to assist you in identifying the various components found on a typical performance carburetor.

Performance Carburetors We Offer

For street use, we've got great values with the Proform Upgrade Series Carburetor, Holley Classic Double Pumper Carburetor, Jet Rochester Quadrajet Carburetor, and Willy's GM604 4-Barrel Carburetor (Chevy models back to 1967), Proform Street Series Carburetor, and AED Performance Ultra High Output Series Carburetor (wide range of vehicles spanning back decades).

Holley Classic Double Pumper Carburetor
The Holley Classic Double Pumper Carburetor.

For light racing and custom applications, we'll start with best values such as the Demon Carburetion Road Demon Carburetor, Edelbrock Thunder Series AVS Carburetor and AVS2 Series Carburetor. Moving up to additional features, there's the Proform Race Series Carburetor, AED Performance Black Dichromate Competition Dominator Carb, and AED Performance High Output Modified Series Carburetor.

AED Performance High Output Modified Series Carburetor
AED Performance High Output Modified Series Carburetor.

For serious racing, the Holley 2x4 Gen III Dominator Carburetor is designed to work most effectively with modified fuel lines that deliver maximum flow. And if your vehicle will be subject to some extreme hard knocks during off-roading, desert use, mudding, and even demolition derbies, check out the custom-designed QFT Off Road Series Carburetor. Typically, these will feature aluminum construction, a high flow rate, stainless steel hardware, adjustable linkages, adjustable air correctors, and more.

Proform Race Series Carburetor
The Proform Race Series Carburetor.

We've also got individual components for performance carburetors such as metering blocks, power valves, jets, metering rods, accelerator pumps, cams, and nozzles, and vacuum secondary diaphragms, springs, and more.

Sample Customers

1975 Pontiac Grand Ville convertible

Sean has owned his 1975 Pontiac Grand Ville convertible for decades. Over the years, his goal was to keep mechanicals pretty much OE stock as he replaced the interior and did paint work to restore things to original condition. Finally, Sean was able to spare a few bucks to get the engine rebuilt and running well. After removing the motor and sending it to a rebuild shop, Sean began considering what type of intake manifold and carburetor he preferred to install while things were being taken apart and put back together. Other than a higher-performance camshaft, Sean opted to keep other engine internals stock - which was in keeping with his main philosophy of keeping value up with showroom originality.

1975 Pontiac Grand Ville
1975 Pontiac Grand Ville

When Sean called our hotline, we used a general engine RPM redline guideline of 5,500 for his engine to calculate a target CFM number to look for in a carburetor. From the factory, his engine's cubic inch displacement (455) is multiplied by max rpms (5,500) to arrive at a number. This number is then divided by 3,456 to calculate the engine's CFM capability.

Since Sean plans on doing easy cruising, the standard street use adjustment number of 85% is applied to calculate a recommended street-use carburetor CFM of 615.49. Rounding up to the next hundred, Sean should look for a CFM of 700 or even 800. (If Sean's engine was being rebuilt with significant upgrades for drag strip levels of racing, the adjustment percentage to calculate CFM would be 110% instead - arriving at a recommended 796.51 CFM target for a Performance carb.)

Edelbrock Performance RPM Single Quad Intake Manifold & Carburetor Set
The Edelbrock Performance RPM Single Quad Intake Manifold & Carburetor Set.

After considering both replacement and performance intake manifolds and carburetors, Sean opted to go with the Edelbrock Performance RPM Single Quad Intake Manifold & Carburetor Set. Sean appreciated how the manifold's lightweight aluminum construction reduced weight over the front wheels, and he appreciated how the included 4-barrel carburetor's 800 CFM rating was right on target to handle just a little bit more horsepower than stock. Plus, the fact that the manifold and carburetor were both engineered by Edelbrock to work together gave Sean a high degree of confidence about their performance and reliability.

1996 Chevrolet Tahoe

Bob's 1996 Chevy Tahoe is like an old friend to him - a workhorse that doubles as transport for his handyman business as well as for his family. Since Bob lives in a warm climate, his truck is still going strong with no rust after over 100,000 miles.

1996 Chevy Tahoe
1996 Chevy Tahoe.

After hearing his engine emit louder and louder sounds from under the hood, Bob noticed it stumble and run erratically. A closer look revealed the plastic upper manifold section had cracked to the point where there were visible gaps in it. Because the 350 V8 was equipped with a fuel injection system in good working order, Bob's only interest was replacing the manifold with a value-priced one that restored factory running conditions.

AC Delco Original Equipment Intake Manifold
The AC Delco Original Equipment Intake Manifold.

Ultimately, Bob chose the Replacement AC Delco Original Equipment Intake Manifold from our website. Because it's made by the same company that built the original part for GM, it will fit perfectly and offer the same quiet, smooth engine performance Bob appreciates. And since AC Delco had built the original parts decades ago, they've been able to gather the most feedback from dealers and other shops about design flaws that caused the originals to fail prematurely. Consequentially, their current manifold features substantial improvements to any and all weak spots. As we mentioned earlier above, this is just one example of a better-than-original OE intake manifold that can be found on our site.

1993 Ford Mustang LX 5.0

Having previously owned a 1993 Ford Mustang LX 5.0 decades ago, Jimmy found another '93 notchback coupe in original, pristine condition in time to purchase as a 50th birthday present for himself. In the old days, Jimmy took his old LX to the track - keeping it street legal for everyday use. But since he won't need his new 5.0 as a daily driver, Jimmy decided to make it track-use-only - trailering it to the races with his SUV.

1993 Ford Mustang LX 5.0

Jimmy looked to start light, adding new performance items such as a cold air intake, fuel injectors, throttle body, custom exhaust system, and more. Because he didn't want to add a supercharger or turbo, he sought to increase airflow into the engine with a performance intake manifold. And, he wanted to keep the hood panel looking stock.

Professional Products Typhoon Intake Manifold
The Professional Products Typhoon Intake Manifold.

After looking at the choices available, Jimmy selected the Professional Products Typhoon Intake Manifold. With aluminum construction that saved weight and a durable finish, Jimmy knew it would continue looking and performing well for a long time. But mainly, it provided maximum airflow for his performance desires.

Repair Vs Performance Parts Intake Manifolds Carburetors Main Gallery

To sum things up, if you want to keep things simple and recreate the lifespan, reliability, and performance of your vehicle's intake manifold assembly, you'll be very satisfied with our replacement OE-style units - many of which provide improvements over factory parts you'd pay more for at a dealership.

And if you've got a classic vehicle with a carburetor that's past its prime, replacement carburetors (and intake manifolds) are a great way to restore factory levels of performance with no fuss and no muss. If the rest of your engine hasn't been modified, replacement components will also maintain factory originality throughout the vehicle - a big plus when show car judging points are a factor. Putting your ride up for sale? Remember that buyer interest and selling prices tend to increase with originality.

For those seeking to create more power, a performance intake manifold is a must in order to create the higher air and fuel flow rates you'll need. And if your vehicle has a carburetor setup, swapping your original for a performance manifold with multiple carburetors is an easy way to muscle things up.

We understand you may have questions about what you see on our website. We're happy to help make your shopping experience easier, so we've got knowledgeable product reps on call seven days a week that will be glad to listen and share any expert advice possible - without high-pressure sales tactics. We look forward to hearing from you!

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