Carb spacer shape

[Fredensborg]

I am prepping my mustang for a new carb, and wondering what to do about the spacer...I am going to get a new 1/2" one because the old one is starting to fall apart. My question is what "shape" spacer to get? My intake is a Edelbrock Performer and has a "divided" mouth. 2 openings, one to the left and one to the right. However my old spacer just has one giant square hole with rounded corners. Wouldent I be better of with something that matches the intake opening? something like this ----->http://www.jegs.com/i/Edelbrock/350/8725/10002/-1

Or does it not really matter that much?

 

[Don C]

Yes, it would be better if you have the one that matches your manifold. The wide open spacer is for a single plane manifold and likely adversely affects the performance of your dual plane manifold.

 

[Fredensborg]

Yes, it would be better if you have the one that matches your manifold. The wide open spacer is for a single plane manifold and likely adversely affects the performance of your dual plane manifold.

 I figured that I should match up the shape. But again, I'm learning as I go here...so I hope you guys don't mind a few stupid questions from time to time. ::thumb::

 

[Vinnie]

I bought a phenolic (plastic) spacer with 4 holes and put it on a Performer intake as well. I also used gaskets with 4 holes but I cut the gasket between the spacer and the manifold so the gasket has 2 holes that match the intake. I do believe having a 4 holes spacer underneath a 4v carb has positive influence on airflow inside the carb (I was told anyway...)

 

[Don C]

I agree, which is why I have a four-holer on mine, to help with the torque on my 351C 4V. I don't know how much, or if, it helped. No torque on 4Vs is a myth, as far as I'm concerned. Mine accelerates from a stop quite well. I've had some fairly quick cars, and this one is right up there.

 

[Twins]

Jason: I believe that is the one I have between the carb and the Edelbrock manifold. Just make sure you have the clearance if for example you are running ram air and this spacer is larger than whatever you had in there.

Let us know when you get the car running.

 

[flstf09]

Spacers can kinda be a black art,what works for one engine doesn't work for another.I doubt you will feel much difference with it just being a 1/2 spacer....but.If it's just a mild street engine I'd wager the 4 hole spacer might have a little better "feel".I run a combo spacer on mine 4 hole tapered to mostly open on an open plenum intake and it made modest power differences over a straight 4 hole or open spacer.Mine is not a super mild engine though.Spacers are cheap and easy to change buy a couple and see how they feel to you.

 

[c9zx]

Strange that the dual oval spacer seems to come with full open gaskets. +1 on DonC's post  regarding the myth that 4V's don't make torque. Poor choice of parts makes no torque. Chuck

 

[TommyK]

Jomar makes a spacer called an "Equalizer" that has a bathtub shaped opening on one side and two holes on the other which really works well on a BBF with the Eddy Performer manifold which has a fully divided plenum. The bathtub side goes over the side of the plenum with the high step and the 2 hole side goes over the side with the lower step. I made one from a standard 1" 4 hole spacer and it seems to make a difference. Engine builders on the BBF sites say dyno testing shows it worked better than either a plain 4 hole or open spacer.

Might be worth looking into.