spread bore to square bore adapter

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83K5guy

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I picked up a 1406 eddy off CL for $40 its clean supposedly it was used once then went with a demon. Any how I don't want to swap intakes just yet and was wondering if the adapter for the spread to square are better then others. I read the open spacer types have negative effects but if you have the one just holes machined it works better. I know Jason (Irishman) has the open one. Just want some opinions.

Spacer style like Jason has
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Hole style
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Tyger13us

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I picked up a 1406 eddy off CL for $40 its clean supposedly it was used once then went with a demon. Any how I don't want to swap intakes just yet and was wondering if the adapter for the spread to square are better then others. I read the open spacer types have negative effects but if you have the one just holes machined it works better. I know Jason (Irishman) has the open one. Just want some opinions.

Spacer style like Jason has
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Hole style
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edit.....

a 1 inch spread bore to square bore adapter and to even help it out more,, us a square-bore 1 inch spacer with the 4 holes on top of that.
it will give ya alot more low end torque/throttle response with good air to fuel mixing in the spacer area.....

i use that combo on my truck and it works perfect....

they do make that certain spacer type special,, but ya dont want to pay for what they want for one....
 

Tyger13us

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i missed your pics,, id still use the one ya got and put a 4 hole 1 inch spacer on top of that.. works good......
 

Swims350

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used ONLY those with 4 holes to do the exact same thing, spreadbore to square works perfectly. I was told to use only the 4 holes to keep the mixture right, but I thought eh.. but they work and work fine to adpt that carb to that intake just fine.
 

bucket

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I think it depends on each motor, I think some will like the open adapter better while others will like the 4 hole adapter. One thing I don't like about the 4 hole adapter is that the primaries of a quad are very small, so the primaries have to neck down in the adapter. The open adapter doesn't have this issue.

With that said, I run the 4 hole type adapter on my truck. I'm not worried about a possible slight airflow restriction on a stock 305.
 

83K5guy

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My thought was with the open spacer style is fuel will hit the spread bore part of the intake as it goes down being its four holes as with if you had the four hole adapter it can only be atomized down the holes. If that makes since to yall, but either should be fine for adapting it to the intake.
 

GreaseDog

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Pretty sure you can bolt a 1406 to a stock intake. No adapter needed.
 

crazy4offroad

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Pretty sure you can bolt a 1406 to a stock intake. No adapter needed.

Not sure about a stock intake but an aftermarket spreadbore intake flares out for the secondaries, and the 1406 will have a small gap on both sides. But if the stock intake has the 4 holes like that adapter pictured above then it should bolt right on.
 

Swims350

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they flaps or butterflies won't clear a 4 hole intake, being small quadrajet fronts and the eddy being larger they won't open up all the way.
 

crazy4offroad

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The butterflies on a 1406 are the same size front & rear, q-jets have the larger rear butterflies.
 

Swims350

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yea that's what I said, quadrajet intake 2 small and 2 big, edelbrock carb 4 same size like a holley and they are larger then the quadrajet intake holes. thus when opened far enough without a spacer they hit.

the aftermarket intake you mentioned with the small holes not covered they make a small bolt on plate for that.
 

83K5guy

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I tried to put it on just to see and anything over 1/4 the butterflies.hit so I guess I'll be buying the for hole adapter. I did see I have a 1" plastic spacer.

I'll probably go this way

http://www.amazon.com/gp/aw/d/B00062YACG
 

Swims350

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I knew it hit lol I tried it too on old mans 86 when we put the 1405 on it. I think it was 1405, it's the 600cfm man. choke.
 

GreaseDog

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That's the 1405.

just tried the 750 I've got here for the firebird, same thing, 1/4 throttle. Bolts right on though.
 

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