Squarebore-Spreadbore Adapter

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daginsu

daginsu

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So I have a Holley Street Avenger 670 and an Edelbrock Performer intake. The carb is square bore and the intake is spreadbore. I know that there are several adapters out there that will make this work, but I also see a big difference in the design and price of them.

The Edelbrock 2696 looks like a nice piece, but it's $30 and it quite a bit taller (0.85") than the simple ones: http://www.jegs.com/i/Edelbrock/350/2696/10002/-1?CT=999

The Jegs 15440 looks decent also and it's only $14. But it's still pretty thick at 0.75", plus the gaskets: http://www.jegs.com/i/JEGS/555/15440/10002/-1

The Edelbrock 2732 is about as basic as it gets, it's only $6, and only 1/16" thick: http://www.jegs.com/i/Edelbrock/350/2732/10002/-1?CT=999

I'm sure the 2696 is a good piece, but will it matter on a mildly built 318? I think I'm more concerned about hood clearance at this point, so I'm leaning toward the 2732, but I was just wondering if any of you have any experience with these or other adapters.

FYI, this is going on a '76 Scamp.
 
I think your ok due to the fact it has both bolt patterns on your manifold.
 
you need an adapter to cover the wide sec openings, the flat plate works fine, but i bet the adapter makes a bit more HP
 
EL5DEMON340 said:
BTW i would pick the jegs one out of the three.
Click to expand...

Ok, thanks for the input. I guess worst case if I get the Jegs one and it's too tall/thick, I can sell it and go buy the cheapy plate and still be out less money than the cost of the more expensive Edelbrock.
 
I have the flat plate if you want it.
 
"Carter" square bores will work from the Edelbrock description.
"Carburetor Recommendations: OEM 4-bbl
Edelbrock Thunder Series AVS or Performer Series carb, 600-650 cfm (see Carbs & Accessories), use our #1481 or #1843 Throttle/Transmission Lever Kit "

I also checked on my 71 340 TQ intake and the stock AFB gasket seals to the manifold.

EL5DEMON340 said:
you need an adapter to cover the wide sec openings, the flat plate works fine, but i bet the adapter makes a bit more HP
Click to expand...

I think you are right. I have not had a "Holley" carb for decades. They probably do not seal the big secondary bores.
 
daginsu,
Did you ever try any of these adapters? Like you, not sure if the 15440 is really required if the 2732 works...i too am worried that the 15440 is too thick...
thanks
 
Patrick said:
daginsu,
Did you ever try any of these adapters? Like you, not sure if the 15440 is really required if the 2732 works...i too am worried that the 15440 is too thick...
thanks
Click to expand...

Sorry, I haven't got any of them yet. I won't be able to get the big stuff until after the beginning of the year so it might be a while before I worry about ordering the adapter. I can't remember who it was, but someone was offering a free one on this thread somewhere if you want to try it...if he still has it.
 
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