Unfortold "Carb Spacer" Power?

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DEVIOUSDUSTER

DEVIOUSDUSTER

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In a recent issue of Car Craft they did an article on "Low Buck vs High Dollar" speed parts. Items covered were things like standard heads vs CNC, 2.5 vs 3.0 inch exhaust, and early dual quads vs RPM air gap. All were tested in great detail with some pretty eye popping results. But the segment that really grabbed my attention was the four hole vs tapered carb spacers. This is power that seems really cheap to obtain but I feel is overlooked in many applications. If anyone could shed some light on the topic it would be greatly appreciated. Their test mule was a small block Chevy stroker. I'm debating going with the four hole 1" spacer made from that Phenolic plastic on a 360 seeing 6,000 blasts. Let me know what works!
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66340SEDAN said:
I run a 1" Super Sucker 4 hole aluminum spacer on my 340, it is all machined and tapered on the bottom side, here is some info from their site.

http://www.cfm-tech.com/HVHdominatorspacersdynotest-1.htm

http://www.cfm-tech.com/nationaldragsterarticlehvh.htm
Click to expand...

It sounds like this company makes a great spacer for the Holley. The price tag seems a little steep. It would be cool to see it compared to other makes that use the same basic template and carry half the price.
 
I've found them to be helpful on single plane engines. But almost never on dual planes.
 
I have a cheapy 2in for sale if you wanna try it out for yourself..15plus shipping?
 
I'm running a 4 hole on a Weiand single plane for the same reason as above and it did get rid of the off idle stumble. However I'm thinking about reusing it when I install the RPM Performer mostly for heat insulation.

Terry
 
I'm running this one on a 390 in Nikkis 72 F100 with a single plane Streetmaster and it works great. I ran it for a few miles with out the 4 hole piece and it stumbled all over the place and was a dog. I put in the 4 hole piece and that truck has the smoothest acceleration I have ever felt and will boil the rear tire off if you don't foot F it.
100_3389.jpg
 
So the general assumption is that a decent mid-range priced spacer works wonders on a single plane manifold but it virtually pointless on a dual plane/high rise?

I have a stout 360 sporting an Edelbrock Performer RPM w/ a 750 Holley Double Pumper and am debating playing around with some cheapies to see if there really is any difference in performance let alone price...
 
I had mine on the edelrock performer intake and I loved how it helped out, becasue I had a 318 with 3in Exhaust and I lost alot of low end torque but the 2in spacer helped get some of that back
 
I think it's more of a matchign thing. If you have a mismatch, or something that falls where one can't tune it out, they might help. It's been my experience (and just to be honest, I have never dyno tested this to back it up...) that dual planes when properly matched in terms of carb size and camshaft suffer some throttle response loss especially off idle with any type of spacer. The 4hole helps boost the signal to the carb... but a smaller carb will have that same sensitivity and response. While a single plane intake, where it is sized right and chosen right matching the cam, and carb, and rpm range, can benefit by adding plenum and shaping the mixture because it will change the wave tuning in the intake, more evenly distribute the mix thru all 8 ports, and slow down the mix so it can make the turn smoother without seperating. The Super Suckers also smooth the turbulence found right under the throttle plate. It works like an airfoil and can increase cfms, therfore increasing power. How much depends on how bad the intake is to begin with and what you're doing with it. I've only used open spacers. Without a dyno, I can't see the benefit from simply swapping spacers.
 
The article 440Duster submitted is really consice and informative. (Thanks a ton) Does the carb linkage have to be changed on the 1" and 2" spacers?
 
mine dident, and it was stock linkage, but Never know till you try
 
DEVIOUSDUSTER said:
So the general assumption is that a decent mid-range priced spacer works wonders on a single plane manifold but it virtually pointless on a dual plane/high rise
Click to expand...

I would'nt say that.. i run a 1' open wood spacer on both my 416 and 360,with an Air Gap intake the results i've had speak for themselves....
 
Definatly horsepower to be gained or lost with spacers. Have seen it first hand on the dyno.
 
Funny to read this now. Back in the early 80's when I had my first V8 Barracuda I couldn't afford to do a lot of modifications. Changing from the 2v over to a 4v carb was too evpensive for me. What I ended up doing was getting a larger 2v off a 383. The carb was too big for my manifold so my shop teacher in high school and I made a 1" spacer that acted like another set of venturies allowing the air fuel to freely flow into the smaller manifold. We als had to make some offset studs as the bolt patterns were different. I also made an air cleaner that looked stock height so when you looked under the hood you had no idea. That car really ran great after that and no one could figure out why it ran so stout for a basically stock car. The Chevy guys hatted my car.
 
I have a 360 magnum headed LA engine with a dual plane M1 and a 650 Speed Demon on top of it. I use a 1 inch spacer that has the same divider as the intake. I have no stumble at all off idle. The only issue I have is a little eratic idle but that could just be the cam. hehe

Jack
 
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