Good Carb Spacer

[Clsccmro]

I just installed a four inch cowl hood and want to put a carb spacer in. I have a pretty much stock 327 with an aluminum edelbrock intake and 4106 4-barrel carb. What would you guys recommend for a good carb spacer? Is 2" too high? How much more performance will I see from it, etc? Any helpful comments are appreciated.

Thanks everyone!

[LowBuckX]

Honestly seat of the pants you wont feel a difference bettween a basic plastic or a state of the art super spacer. A good 4 hole 1" spacer is all your motor will need. Then use an air filter neck spacer or step up to a bigger filter.

[evan]

What does a carb spacer do? Does adding one always have positive results?

[6'9"Witha69]

What does a carb spacer do? Does adding one always have positive results?

No. In fact too much spacer will hurt the power in some engines.

Get a bigger filter. No more than a 1" spacer.

[fishtail8]

Get a supersucker.....

[LowBuckX]

Get a supersucker.....

And why?

[Steve68]

HVH makes the Super Sucker, proven dyno HP, BUT, is it proven dyno HP on everyones engine combo, I want to try one,

[chicane67]

Open spacer = increased plenum volume, better mid to high rpm power.

4 hole space = minimal increase in plenum volume, more stable airflow under the throttle plate/butterfly and increased venturi velocity. Better low to mid rpm power.

HMV super sucker = a combination of both.

Engine builds are different and their individual needs will also be different. To say that one should run no more than 1.00" of spacer... is ill advice. To little or too large of a spacer can 'hurt' power production... it goes both ways.

Spacer materials... I would go as far to say the the newer composite and phenolic are the two best. I ran a 1/2" four hole on one engine and it made a world of difference. The carb was cooler, it picked up a couple of points in vaccum from a base lengthening under the venturi and it made some decent power. I also ran an open 1.00", a four hole 1.00", a combination of a 0.500" open and 0.500" four hole, a 0.500" four hole and a 1.00" open... anyways, what worked the best for that peticular engine was the 0.500" four hole phenolic.

I have also found that automatic cars liked open spacers more than four holers... and manuals like the opposite.

Wilson Manifolds make probably the best spacer on the market.. not to mention, the best selection of configurations. There is some explaination of each individual type and some light tech. Their spacers are available in 1/8" increments just for your tuning needs.

[Clsccmro]

Will the bolt pattern for any of these spacers fit edelbrock cabs? What's the difference between the edelbrock and holley bolt patterns? Also, did any of you increase the carb jet size when you installed a spacer, i read an article from Hot Rod that advised the jets should get increasingly larger as the spacer gets taller.

Thanks for all the great info guys!

[fishtail8]

I've only seen one engine on the dyno that didn't like a supersucker.... were not talking huge gains... but it's a pickup with increased throttle response across the range.... The only way to know if your combo likes one is to try....

[LowBuckX]

I just installed a four inch cowl hood and want to put a carb spacer in. I have a pretty much stock 327 with an aluminum edelbrock intake and 4106 4-barrel carb. What would you guys recommend for a good carb spacer? Is 2" too high? How much more performance will I see from it, etc? Any helpful comments are appreciated.

Thanks everyone!

I dont think this motor will see any dyno time nor do I think he will feel any power gains by seat of the pants feel.

[6'9"Witha69]

Engine builds are different and their individual needs will also be different. To say that one should run no more than 1.00" of spacer... is ill advice. To little or too large of a spacer can 'hurt' power production... it goes both ways.

Understood and agreed. I was implying that for what this motor sounds to be that too tall would be too much.

[Tech @ BG]

Carburetor Spacers:

Carburetors spacers can be a very useful tuning aid when working on your streetcar, or racecar. A spacer can be used to move the torque and power-band where it is more usable in your application, or they can be used to help work out inefficiencies in your combination.

4-Hole Spacers. As a rule of thumb a 4-hole designed spacer (4 individual holes one under each barrel of your carburetor) will increase your throttle response, and acceleration. They can also move the torque and power-band down in the RPM range. This is accomplished by keeping the air and fuel flowing in more of a column, which increases the air velocity. This can be a perfect addition if your vehicles throttle response is not as good as you’d like, or you’re getting passed when you pick up the throttle coming off of the corning. A 4-hole spacer can also help make up for something in the intake tract being larger than optimal (too large of a carburetor, cam, intake, etc.)

Open Spacers. As a rule of thumb an open designed spacer (1 big hole underneath your carburetor) will decrease your throttle response, and acceleration. They can also move the torque and power-band up in the RPM range. This is accomplished by increasing the plenum area, which will help in the higher RPM’s. This can be a perfect addition if your vehicle has traction problems when accelerating, or coming off of the corner. A 4-hole spacer can also help make up for something in the intake tract being smaller than optimal (too small of a carburetor, cam, intake, etc.)

Combination Spacers. A combination spacer (half 4-hole, and half open) can give you the best of both worlds. Increasing your throttle response, and acceleration over not using a spacer, and increasing or broadening the torque and power-band.

Plenum Dividers. A Plenum divider does as the name implies divides the plenum in an open plenum intake manifold from side to side. These are generally used to help prevent fuel slosh from side to side in high G load Oval-Track, or Road-Race applications. It is common on certain engines to have lean cylinders do to fuel slosh. A SBC oval track engine running on methanol can run lean on cylinders 3 & 5 while cylinders 4 & 6 will run rich. A plenum divider can help eliminate this.

Spacer thickness. Varying the thickness of your spacer will affect how it affects your engine. Normally the thicker the spacer the more of an affect if will have on your combination. Meaning if a ½” thick spacer helps you a little a 2” thick spacer can give you more of the same affect.

Spacer Material. There are many different types of materials used for manufacturing spacers. They all have pro’s and con’s. Wood for example is a great material as far as thermo efficiency, but can wick fuel, which is not safe. Plastic, or composite spacers are also very good at not transferring heat, but are not as strong, and can be harder to modify. Generally Phenolic fiber, or Aluminum is preferred. Phenolic is very good at not transferring heat, but can be hard to modify. Aluminum is not as good at heat dissipation, but can be ported or modified easily to work on specific applications.

Spacer Tuning. Since each spacer will react differently on each combination there is not a right or wrong type. Spacers are a great tool to have to help dial in a new combination, or tune your racecar for varying track conditions. Swapping out a spacer is a very simple change that can have great impact on the drivability of your streetcar, or racecar. Having a couple types, and thickness of spacers around is always a good investment.