Hey Sb seems you like you have played around with spacers quite a bit here is a question you may be able to answer that has always been floating around in my head you may be able to answer... Have you ever had a motor with a 4150 intake that benefitted from a spacer and tried going to a 4500 intake with a turtle in it with the same carb and seen any results? I've often wondered if that may or may not be a better combination but never had the time or money to play around with it.

I added a 4 hole tapered Phenolic spacer to my NA 524 with a Single Plane Brodix HV2000 with a Pro-Systems 950 and the difference was very noticeable. I bought mine direct from JOMAR Performance, they make them in Michigan. Best money I spent for a power adder.

JRider,
What you putting that engine in, your cat?
Just curious

naturally aspirated 468 Chevy. 1"- 7hp total gain, 2"- 20hp total gain at 5500, lost a couple in the middle, but picked them up around 4800. They're still on those engines!

Just an update. Talked to valako and he said there is no question, go with a 2" four hole molded/ported as the super sucker above...in fact that is what i ordered. He did say run an AF gauge to be safe.

Are spacers ever used in boosted applications ?

Not sure how much that would work, as the carb being on top of the blower wouldn't really affect the plenum size. But, maybe SB or someone could chime in on whether or not it would affect the signal to the carbs on a roots blower.

I run some special holley base gaskets that are 5/16" thick. They have crush collars at the mounting holes. They help work as a heat insulator between the blower and the carb. Mercury used them on the 800sc engine.

http://www.summitracing.com/parts/HLY-108-12/

Thought I answered this...guess not.

I have not tested a 4150 carb on top of a 4500 intake manifold. Sounds like a 'rules restriction' to me and i have not been a part of.

I'm pretty sure one of the Offshore Racing classes had some sort of rules like that cause I remember talk about the HV-300 Adapter on 4500 intakes. Brodix has 4500 intakes that are drilled for the adapter.

HV-300 (adapter upside down so you can see the design)
http://static.summitracing.com/globa...hv300_w_ml.jpg

and intake like the Brodix 2001:
Notice the extra threaded holes on carb flange of intake to place the adapter:
http://www.jegs.com/images/photos/10...158-HV2001.jpg

If you are referencing the 'Turtles' that go on the floor of the plenum I only got into them with restricted rules racing especially 2bbl's. Didn't get my Mojo going much but the one's with ribs did a little for lower rpm and starting / idle on intakes with no ribs on the plenum floor....which a lot, but not all, aftermarket intakes don't have. See'm more on dual plane intakes vs single plane.

So.....I have a whole lot of nothing for you on both regards. LOL.

Yes, but the biggest use I see is for Blow Thru. Get the column of air as freakin straight as possible (over the carb of course, and the tapered spacer under the carb will help that somewhat also.)

I tight turn going into the carb is tough !!! I'm sure you read about all the different hats and what not, and seen cars that aren't restricted hood height wise that have the carb bonnet way above the carb.

Blended spacers not only help with adding some airflow by making the air less turbulent, but more importantly help the carb do it's job better by doing the same....making the air less turbulent. Booster needs this to draw fuel correctly.

Many get fascinated by the air, but the shhh secret is to get the fuel metered correctly and into the intake ports correctly.

If a Spacer get's you more than 20hp on an engine where the carb is sized correctly, chances are your carb isn't all that you think it is. Especially in the fuel metering department.

Hey Deep... To answer this yes... Although not required, we did add spacers to my setup, reason being is the Holley's kept loosing carb stuff down the throat and trashing the blower. My old carbs lost a Booster down blower along with an overflow tube.

We opted with the new build to side on precaution and add a screen gasket for the dual carb setup. With the screen gasket, you have to put a spacer in there otherwise the butterflies will hit. We threw 2 of the Wilson Black Anodized spacers on them and to be honest don't know if it helped or not, but having screens is added insurance on the blower, especially after an expensive 3 lobe helix conversion to an old school B&M 420.