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Old 11-05-2012, 07:28 PM   #1
savatreatabvr
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SquareBore to Spreadbore Adaptor Plate! (Is it Necessary?)

As you all know I have my share of issues with my mid 70's 454 so when I came across an almost new Edelbrock Performer 1407 carb for a great price I bought it on the spot! Of course I didn't flip it over to see if it was a spreadbore until the next day and of course it's not! Can I bolt a squarebore carb to a spreadbore intake without an adaptor and make it run right?
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Old 11-05-2012, 08:00 PM   #2
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Re: SquareBore to Spreadbore Adaptor Plate! (Is it Necessary?)

Without an adapter or squarebore intake it wont run right. I know people who don't even like the adapter ideas. I hope this answers your question.
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Old 11-05-2012, 08:10 PM   #3
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Re: SquareBore to Spreadbore Adaptor Plate! (Is it Necessary?)

you have a aftermarket intake?
i bolted my eddy 1806 i think 650 cfm to a performer 2101 intake
it worked fine for me
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Old 11-05-2012, 08:11 PM   #4
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Re: SquareBore to Spreadbore Adaptor Plate! (Is it Necessary?)

I had an adapter on mine, I wouldn't recommend it, best bet would be a matching intake manifold.
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Old 11-05-2012, 08:19 PM   #5
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Re: SquareBore to Spreadbore Adaptor Plate! (Is it Necessary?)

I used an adaptor on my 440 Moho and it worked great! As far as I know the only difference is the size of the back two barrels, right?
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Old 11-05-2012, 08:35 PM   #6
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Re: SquareBore to Spreadbore Adaptor Plate! (Is it Necessary?)

Just buy the adaptor
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Old 11-05-2012, 08:35 PM   #7
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Re: SquareBore to Spreadbore Adaptor Plate! (Is it Necessary?)

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Originally Posted by savatreatabvr View Post
I used an adaptor on my 440 Moho and it worked great! As far as I know the only difference is the size of the back two barrels, right?
Right.

I'm not morally opposed to a carb/intake adaptor.

I hop back and forth between a Dominator (for unlimited use) and a square flange Holley (for nostalgia classes) by using a Wilson adaptor.

My engine makes about 950 hp, car goes 9.80s at 3950 lbs.

Seems to work ok -

K
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Old 11-05-2012, 08:57 PM   #8
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Re: SquareBore to Spreadbore Adaptor Plate! (Is it Necessary?)

My application is more for street use, lol but I'll take ya'lls advice and buy an adaptor!

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Right.

I'm not morally opposed to a carb/intake adaptor.

I hop back and forth between a Dominator (for unlimited use) and a square flange Holley (for nostalgia classes) by using a Wilson adaptor.

My engine makes about 950 hp, car goes 9.80s at 3950 lbs.

Seems to work ok -

K
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Old 11-05-2012, 10:31 PM   #9
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Re: SquareBore to Spreadbore Adaptor Plate! (Is it Necessary?)

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you have a aftermarket intake?
i bolted my eddy 1806 i think 650 cfm to a performer 2101 intake
it worked fine for me
An aftermarket intake would be a great way to wake up your truck beaver. I lil more money and time involved but shaving 50lbs and making more power is never a bad idea.
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Old 11-06-2012, 07:30 AM   #10
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Re: SquareBore to Spreadbore Adaptor Plate! (Is it Necessary?)

If you believe in the fuel velocity thing, you need to put the spacer on. With out it, can disrupt air flow because the walls won't be smooth all the way down the venturi's. I say that because some people don't believe in the air flow velocity thing even with a regular spacer on say a fuel injection and such. I do, I think the walls inside of the venturi's need to be smooth to keep the even fuel velocity
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Old 11-06-2012, 11:54 AM   #11
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Re: SquareBore to Spreadbore Adaptor Plate! (Is it Necessary?)

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If you believe in the fuel velocity thing, you need to put the spacer on. With out it, can disrupt air flow because the walls won't be smooth all the way down the venturi's. I say that because some people don't believe in the air flow velocity thing even with a regular spacer on say a fuel injection and such. I do, I think the walls inside of the venturi's need to be smooth to keep the even fuel velocity
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That is with a normal spacer. This adapter actually kills velocity and creates turbulence and not in a good way
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Old 11-06-2012, 02:12 PM   #12
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Re: SquareBore to Spreadbore Adaptor Plate! (Is it Necessary?)

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That is with a normal spacer. This adapter actually kills velocity and creates turbulence and not in a good way
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I have heard you say this a couple times, do you have any proof or dyno sheets to back this up?....just curious
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Old 11-06-2012, 07:34 PM   #13
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Re: SquareBore to Spreadbore Adaptor Plate! (Is it Necessary?)

I kinda believes it all needs to be smooth but proof is best!

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I have heard you say this a couple times, do you have any proof or dyno sheets to back this up?....just curious
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Old 11-06-2012, 10:20 PM   #14
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Re: SquareBore to Spreadbore Adaptor Plate! (Is it Necessary?)

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I have heard you say this a couple times, do you have any proof or dyno sheets to back this up?....just curious
I had a carb spacer test saved on my computer but the computer is no longer... And I can't find the article again. But take a look and tell me how bending the air almost 80* right as it exits the carb isn't going to be detrimental?

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Old 11-06-2012, 11:34 PM   #15
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Re: SquareBore to Spreadbore Adaptor Plate! (Is it Necessary?)

This is the Mr. Gasket Squarebore to Spreadbore intake manifold adapter I was talking about! It only makes sense to me if it's installed upside down! I think I need your's INCIDIOUS '86!



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Old 11-07-2012, 08:10 AM   #16
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Re: SquareBore to Spreadbore Adaptor Plate! (Is it Necessary?)

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I had a carb spacer test saved on my computer but the computer is no longer... And I can't find the article again. But take a look and tell me how bending the air almost 80* right as it exits the carb isn't going to be detrimental?

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never seen one like that, Im referring to the all open adaptor spacer, dont see how that can be as bad as you make it out to be.
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Old 11-07-2012, 08:13 AM   #17
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Re: SquareBore to Spreadbore Adaptor Plate! (Is it Necessary?)

savatreatabvr, (didn't get that until I tried to say it!), I think I have one of the open Q-jet to square bore adapters, it's yours for shipping if you want to give it a try.
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Old 11-07-2012, 08:14 PM   #18
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Re: SquareBore to Spreadbore Adaptor Plate! (Is it Necessary?)

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I had a carb spacer test saved on my computer but the computer is no longer... And I can't find the article again. But take a look and tell me how bending the air almost 80* right as it exits the carb isn't going to be detrimental?
who makes that?....ones I see on summitracing and jegs are open plate designs so there is no "bending" of the air as you claim that one has.
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Old 11-07-2012, 08:29 PM   #19
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Re: SquareBore to Spreadbore Adaptor Plate! (Is it Necessary?)

Mr. Gasket from Checker Auto Parts!

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who makes that?....ones I see on summitracing and jegs are open plate designs so there is no "bending" of the air as you claim that one has.
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Old 11-07-2012, 08:31 PM   #20
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Re: SquareBore to Spreadbore Adaptor Plate! (Is it Necessary?)

I'll try anything at this point!

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savatreatabvr, (didn't get that until I tried to say it!), I think I have one of the open Q-jet to square bore adapters, it's yours for shipping if you want to give it a try.
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Old 11-07-2012, 09:00 PM   #21
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Re: SquareBore to Spreadbore Adaptor Plate! (Is it Necessary?)

Like I said in my first post, is a Squarebore to Spreadbore adapter necessary? I do believe bolting a Squarebore carb to a Spreadbore intake can disrupt the air flow and hurt performance but I'm not running a 9 second car, I'm driving an old high mileage big block! I'm going to bolt it on and see what happens, I'll keep you all posted!
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Old 11-07-2012, 09:30 PM   #22
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Re: SquareBore to Spreadbore Adaptor Plate! (Is it Necessary?)

Is it a stock, cast-iron intake? If so, you'll need the adapter. Since it's an edelbrock carb you really should use the ported style adapter. Edelbrocks PN is 2696.
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Old 11-07-2012, 10:25 PM   #23
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Re: SquareBore to Spreadbore Adaptor Plate! (Is it Necessary?)

Yes it's stock and yes I know I need the #2696 but here's what I was told about the 2696! Lopers, (a High Performance Shop here in Phx) said the Edelbrock 2696 Squarebore to Spreadbore adapters have a tendency to crack and cause minor to severe vacuum leaks! I didn't know if I should believe him or punch him, lol, so I walked away empty handed! Ya know a big block aluminum squarebore intake manifold doesn't sound like a bad idea now, Lol!

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Is it a stock, cast-iron intake? If so, you'll need the adapter. Since it's an edelbrock carb you really should use the ported style adapter. Edelbrocks PN is 2696.
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Old 11-07-2012, 10:40 PM   #24
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Re: SquareBore to Spreadbore Adaptor Plate! (Is it Necessary?)

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Like I said in my first post, is a Squarebore to Spreadbore adapter necessary? I do believe bolting a Squarebore carb to a Spreadbore intake can disrupt the air flow and hurt performance but I'm not running a 9 second car, I'm driving an old high mileage big block! I'm going to bolt it on and see what happens, I'll keep you all posted!
The spacer is there to make sure that the gaskets seal correctly. And the bolt pattern matches between carbs
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Old 11-07-2012, 11:47 PM   #25
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Re: SquareBore to Spreadbore Adaptor Plate! (Is it Necessary?)

Yes it's stock and yes I know I need the #2696 but here's what I was told about the 2696! Lopers, (a High Performance Shop here in Phx) said the Edelbrock 2696 Squarebore to Spreadbore adapters have a tendency to crack and cause minor to severe vacuum leaks! I didn't know if I should believe him or punch him, lol, so I walked away empty handed! Ya know a big block aluminum squarebore intake manifold doesn't sound like a bad idea now, Lol!

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Originally Posted by i8tokyo View Post
Is it a stock, cast-iron intake? If so, you'll need the adapter. Since it's an edelbrock carb you really should use the ported style adapter. Edelbrocks PN is 2696.
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