dual plane spacer.

[Badarse mopar]

Can anybody tell me if I need to use a spacing block between the carburetor and the manifold.My car has a carter 500cfm 4bbl and it is bolted to an edelbrock performer RPM manifold.There is a spacer under the carburettor at the moment but it looks to be off a single plane manifold as it has one huge hole in it.Do I have to use this spacer to stop the fuel boiling in the carburettor,and are there dual plane spacers available.Also what is the benefit off using these spacers?

[powerdodge]

you can buy spacers in many shapes!

with a dual-plane intake, the carb will be split in 2... and 4sylinders use one side, and the rest the other..

IF you put on a spacer that have only a big hole,all synlinders can use the whole carb..the engine sees a bigger carb! maybe a little more top end hp.
depends on the hight of the spacer,and engine setup.

you can get a spacer split in 2, for dualplane, and spacer with 4holes, and so on.. many shapes..

the main reason I guess is to get a bigger plenum ,and a stronger signal to the carb(at least with spacers with 4holes, making the air pass faster in the venturi,and in a better way), making it able to "tune" the fuel/air ratio better... may result in better milage and more hp.

baut the fuel boiling, it's recommend to have a spacer yes! from my piont of view, as long as the engine is stock, you will be fine without... (if you absolutely have to throw it away...)

does it make any sense? I'm not any good in english...

[jelsr]

Nothing wrong with your English, Daniel. The only thing I might add is for an insulator/spacer it should be non metallic so it does not conduct heat from the manifold to the carb.

[rumblefish360]

Daniel, your English is better than mine.

Badarse;

If you have a problem with fuel boiling, a spacer is just the ticket to help out. Plastic/phelonic resin types are very good at keeping heat away. Most spacers are made from this material.
The "Other material" is aluminum. There is also wood, but I'd stay away from it on a street car.

Types of spacers;

As said above, there are a few types. Open, just a big square, divided, a big square with a wall inbetween, and a 4 hole spacer. They also come in different thickness. Mostly like 1/2, 1 or 2 inchs.

Bennifits of the different types;

A open spacer gives more top end power. The area under the carb, in the intake manifold is called a plenum. Adding an open spacer increases the plenum area. More plenum, more time there is for the fuel to atomize.
(Thus the reason for more power (When properly tuned) on any engine, but the spacer should be the right one for the combo. Open spacers are NOT a garunette for power.)

Divided spacer does much the same as an open spacer but keeps the intake a dual plane in total. The carb is still feeding the engine as if there is no spacer, but just added plenum for fuel atomization.

A 4 hole spacer almost allways adds torque. The spacers 4 holes aid in atomizing the fuel bbl. by bbl. The hole per bbl keeps the fuel moving fast where in a open spacer, it tends to slow down.

[TK]

mr gasket makes a plastic spacer with 4 holes, i use them.
with the 500cfm carb, i would use it, cause torque is what your combo is good for