Which spacer is best?

[67_Slimer]

So I'm contemplating running a carburetor spacer and have some questions. I have a 340 stock stroke , 10.5/1 , .525 solid cam with 1.6 RR , Eddy aluminum heads , Victor intake with a brawler 750 , 4 speed and 4.56s. I've had numerous people suggest a carb spacer. 1) Are they even worth it? Do they make a noticeable difference? 2) If so what spacer is good for my application? 4 hole? open? also height and material? Thank you in advance.

 

[Heywodja]

Here's a video with Dyno results, this may help..

 

[toolmanmike]

Check hood clearance first then you'll know how far you can go without carving a hole in your hood. Many of the racers use wood. Excellent insulator.

 

[67_Slimer]

Check hood clearance first then you'll know how far you can go without carving a hole in your hood. Many of the racers use wood. Excellent insulator.

I have a six pack hood so clearance shouldn't be an issue.

 

[jbc426]

Wilson makes one of the best. My builder says its worth 15-20 hp on virtually every engine the put it on.

 

[Inertia]

Wilson makes one of the best. My builder says its worth 15-20 hp on virtually every engine the put it on.

Wow, more than headers .
Add an "x" or "h" pipe, gain 40 hp total .

 

[jbc426]

Wow, more than headers .
Add an "x" or "h" pipe, gain 40 hp total .

Good catch, and I would assume lower gains as the motors approach "stock-ness".

 

[Locomotion]

Canton Racing has a wide variety of phenolic spacers including tapered 4-hole. I didn't make any comparisons, but the 1" phenolic tapered 4-hole was what I used on my 360 Dart Sport. Better insulating qualities than aluminum with the tapered bores, or whichever style you choose.

As with most other engine modifications, any changes you make may benefit from re-jetting the carb for optimum results.

 

[forphorty]

I would expect that Speedmaster will have a black friday sale this Thanksgiving. Search results for "carburetor%20spacer"

 

[pishta]

they work on slants too! MAYBE>>>>>

 

[33IMP]

I was gonna comment, but I see I'm a year late.

 

[Newbomb Turk]

So I'm contemplating running a carburetor spacer and have some questions. I have a 340 stock stroke , 10.5/1 , .525 solid cam with 1.6 RR , Eddy aluminum heads , Victor intake with a brawler 750 , 4 speed and 4.56s. I've had numerous people suggest a carb spacer. 1) Are they even worth it? Do they make a noticeable difference? 2) If so what spacer is good for my application? 4 hole? open? also height and material? Thank you in advance.

The only way to know is test. An engine dyno will tell you add 10 inches of spare and it will make more power.

In the car, driving around it will suck. On the track it will be slower, especially shifting three times.

The good news is every single 4 intake like we would run is plenum volume deficient so you won’t hurt power with most spacers.

Test at the track. Watch your MPH. That’s horsepower. ET is bite. Ignore the ET when testing this stuff

 

[33IMP]

Late, but I'll comment anyway, since it's on today's list.
The EM test was not definitive, because each engine combo is different, but....
general rule: open on a split two plane intake. Four hole on a single plane intake.
Best will likely be a tapered. Try the $40 version of the Wilson $200 version.
BUT! Turk is dead right. Test, test, test, and watch mph, for a drag car
How does it drive, is the test for a street car.

 

[crackedback]

The only way to know is test. An engine dyno will tell you add 10 inches of spare and it will make more power.

In the car, driving around it will suck. On the track it will be slower, especially shifting three times.

The good news is every single 4 intake like we would run is plenum volume deficient so you won’t hurt power with most spacers.

Test at the track. Watch your MPH. That’s horsepower. ET is bite. Ignore the ET when testing this stuff

Similar to the straight duals, X or H pipe exhaust debate. All combo dependent.

 

[Locomotion]

As with ANY change (intake, exhaust, cam, etc.) it may be necessary to adjust the jetting for optimum performance. More plenum volume, like a spacer under the carb, may need richer jets (If optimized before any change.) That probability was corroborated while I was testing a Weiand Stealth dual plane intake. 750 DP Holley was square-jetted or very close with both primaries the same and both secondaries the same. I noticed that the plug coloring was lighter in the cylinders being fed by the deeper (bigger) plenum. I ended up with jets 2#'s bigger on the deeper plenum, consistent coloring on all plugs and picked up at least .05. Forgot if it was 1/8 or 1/4 mile. Results may vary with different dual plane intakes. But first clue would be different plug coloring if jetted square or close to it.

 

[PROSTOCKTOM]

At minimum I always run at least a 1/2" thick Jomar Performance, phenolic 4-hole spacer on any engine I deal with if for no other reason to isolate the carb.

Racer engines, or ones that allow for more height I run a 1" Jomar 4-hole Power Cone on an open plenum or depending on the intake I use Magna Fuels shear plate spacers.

However, as other have probably already mentioned spacers do not always provide positive results. Spacers are basically tuning aids and what works really well on

one engine may not respond the same way on another. It's more of a trial-and-error approach to get the correct combination.


Phenolic Carburetor Spacers

Tom