Phenolic Spacer under carb or tb?

65coupei6

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Just as the title states. Does anyone think there is a benefit to maybe a 1/4 spacer?

The reason I ask is because the way the intake is made it needs an adapter depending what carb you are using. This already raises the carb or Efi up. But it is still made of aluminum. Will adding a 1/4" more with a phenolic spacer hurt or better the air flow?
 
I was just reading an article yesterday about using one of those spacers to prevent vapor lock in the fuel system. So there may be more than just one reason to use one.

I put a 1" spacer on my 170ci strictly for carb clearance over a tall valve cover. It doesn't seem to hurt the flow of air at all. In fact, it says they increase HP, but I dont truly believe that.
 
A Carb. spacer made out of a plastic or even wood to keep the heat out of the Carb. is a must. A lot of heat is transfered to the Intake manifold, and that is good. But you need to try every thing to keep most of that heat away from the fuel bowl. The fuel can boil in the fuel bowl, causing it to percolate over out of the Carb. booster venturi. Also helps with vapor lock issues in the fuel line... There are plenty of tests using 1/2- 1 inch spacers. Almost always there is a power increase, 5-10 Horse power on a larger perfomance engine. On a smallish 6 cylinder, im sure its not much.
 
Spacer increase the plenum volume. At least that's 1 theory of how it increase HP. Another is it helps with fuel distribution
 
Yes, and yes... On the simple log type intake manifold, imagine all 6 cylinders taking their turn sucking on the 1 barrel Carb. At idle and low speed, all is just fine. At closer to a maximum engine speed, all six cylinders are fighting for the same hole to breathe through.... You raise the Carb., and increase the plenum volume, on each intake stroke, there is just a little more Air/fuel mixture for each cylinder. All because of the increased plenum volume... Even though it it is slight, it makes a difference.
 
I'm going to say that a spacer of only 1/4" would only benefit as an insulator. Now if you go to say a 1" spacer you will be doing something more
 
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