Carb Spacer on a 318?

Fuel and Air Systems

  1. 74Runneer

    74Runneer Well-Known Member

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    I have a 318 with a mild cam, headers, 1406 600 cfm eddy carb, performer intake, and #302 casting heads that bring my compression up to around 9:1.


    My question is: has anyone seen any real results when using a carb spacer on a setup similar to mine? I see ads that claim a hp gain of 10 or more but what can i actually expect? I don't race, i just drive on the streets and like to drive it like i stole it occasionally. So im thinking about buying a 1" 4 bore spacer.


    Is this just a hit or miss kind of thing where i just have to try and see which one works best? I dont have access to a dyno or drag strip.
     
  2. 67 coronet

    67 coronet Well-Known Member

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    only time a carb spacer will improve things is if your intake does not match the rpm power band of you cam.every inch of spacer moves the intake power range up a few hundred rpms.it can make a diff on a circle track type car,but not so much on the street.(as long as you have a decent intake)you can often cause more problems then its worth.
     
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    • Propwash

      Propwash Well-Known Member

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      Seems like a lot of the spacer MFG's have a lot of pipe dreams when it comes to HP ratings with a spacer, but never the less there are proven gains, especially when it comes to the thicker spacers on the bigger motors. A few things a spacer will do for you. One, it can and will help with heat issues such as vapor lock or fuel boil in the carb. The added distance from the block as well as phenolic materials or even wood composite will tame down hard starting after sitting for a bit, if it's a fuel/heat related issue going on. A 4 hole spacer will give you more low end torque and better idle quality. An open bore spacer will grab you some more HP/TQ, but like 67 mentioned, it moves that to a higher RPM. Basically it's like a little baby tunnel ram adding more plenum space.
       
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