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Discussion Starter · #1 ·
1. What is the purpose and function of a carburetor spacer (insulate carb, provide more mixing volume to alter HP or torque, etc ????)

2. I've a Mk-III, 351W, Energy Suspension motor mounts, a FMS dual-plane intake, and a Holley 670cfm Street Avenger (4150). I would like to use an oval Cobra breather, but based on other posts I've seen, I'm already concerned it won't fit due to interference with the body. Will I have room for a spacer under the carb?
 

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Sherrell,
The purpose and function are kinda all of the above, that you mentioned; insulate the carb from the heat of the motor (e.g. phenolic spacers), inrease the effective length of the intake runners, create "swirl" as the mixture enters the intake (maybe improves air/fuel mixing?) ...probably several ways to increase efficiency, torque, horsepower, depending on the type. I had one on the Capri when it had a dual-plane intake, the spacer was called Torque-Swirl or something, that did slightly improve the seat-of-the-pants feel, probably was worth a few lb-ft.

For your car, probably around 400 hp and 400 lb-ft in a 2100-lb car, I wouldn't think slightly more torque or hp would make much difference, I think you'll have plenty regardless. I guess I would worry more about hood clearance than those incremental power gains. I think I have an old spacer someplace; if so I'll bring it along with the studs, if you want to try a mock-up to check clearance/height.
Charlie
 

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The main purpose is to taylor the torqe and peak horsepower curves. The taller the spacer the more low end you'll loose and the more upper end you'll gain. These cars stock already are not hurting at all on low end. Mine dosent fall off now till over 6000 rpm and still pulls to 6500. I'm running a 1" spacer with basically the same manifold you have with only some port matching. Clearance is another thing. My oval air cleaner would not clear the distributor with the manifold I'm running so I put the spacer on, gained more top end power and still have about an inch before it hits up top.
 

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Discussion Starter · #4 ·
Charlie,

You are the man... I was kind of hoping that for $29.95 I could double the HP and triple the torque???

BTW: I measured the carb stud hole depth in my manifold. It's .75". The carb flange is .5", so a 1.7" stud should be almost perfect without a spacer???
 

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Sherrell,
That sounds about right on the depth/stud length.

Lex makes a really good point about the oval air cleaner clearing the distributor - that could make a spacer a "must."

The NASCAR guys have run Wilson spacers, of exotic material and design I think(and definitely pricey). I would assume Wilson makes some for less than wide-open-throttle applications; if so, one of those would be interesting to try.
 

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Sherrell,

Not to scare you but I think I have the same basic setup without the spacer and there is no way I could fit a 1" spacer and still have room left over. I have maybe 1/4"-1/2" (I could measure exactly tomorrow if you want) clearance.

The one difference we do have is I have the rubber (convertible?) mounts and not the ES mounts. I know that makes a difference but I am not sure in which direction or by how much. I'm sure someone could chime in on this. HTH.
 

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Discussion Starter · #7 ·
Thanks guys. All helpful info. I think I'm just going to go without a spacer for now and worry about inserting a spacer after the body is on and I have some run-time under my belt...

Sherrell
 
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