Square bore to not so spread bore?

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IdahoCarson

IdahoCarson

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I bought a 400 cfm AFB for my Dutra intake. I have a square bore to spread bore adapter, it will bolt on but seems like it will be… turbulent. I’m not sure what adapter I need but here are some pictures of what I’m looking at. Any recommendations or parts numbers would be appreciated.

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As always thank you, Carson
 
You need a different carburetor. That's the early small flange Carter.
 
You can or used to can get square bore adaptors that had the 4 holes and would allow you to rig the thing to fit the wide/ narrow bolt pattern. They normally came with special shallow head bolts that went into hex holes in the bottom of the adapter, to stick up into the carb. If you find one used, you can make those bolts by grinding the heads a little bit on common 5/16 bolts.

The mount holes are set up similar to the adapter in your photo, only the throat bores got straight through
 
Thanks for the information and advice. I’ll drill the manifold as a last resort. I’m going see if I can scrounge up an adapter. I’m going to check if my machinist buddy can make me one at work. We’re going to be on night shift soon we should get away with it.
 
IdahoCarson said:
Thanks for the information and advice. I’ll drill the manifold as a last resort. I’m going see if I can scrounge up an adapter. I’m going to check if my machinist buddy can make me one at work. We’re going to be on night shift soon we should get away with it.
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The only adapters with those patterns I can find are just like what you have. If we could see a picture of the intake flange itself, that might be helpful.
 
I would get a carburetor that'd bolt directly to that. Any of the Edelbrocks will, I believe.
 
RustyRatRod said:
I would get a carburetor that'd bolt directly to that. Any of the Edelbrocks will, I believe.
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The problem I have with that is the smallest Edelbrock is 500 cfm. That’s a bit optimistic for the slant I’m building. This is the Carter 400 of a 273 66’ Barracuda. I could run a Holley 390 but much prefer Carters. I was hoping there was an off the shelf adapter but if I have to get one made it won’t be a too big of a deal. I have a few buddies that are machinists in the refinery’s I work in.
 
IdahoCarson said:
The problem I have with that is the smallest Edelbrock is 500 cfm. That’s a bit optimistic for the slant I’m building. This is the Carter 400 of a 273 66’ Barracuda. I could run a Holley 390 but much prefer Carters. I was hoping there was an off the shelf adapter but if I have to get one made it won’t be a too big of a deal. I have a few buddies that are machinists in the refinery’s I work in.
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Quick Fuel makes a Holley style 450 vacuum secondary. That's what I have on mine and it runs great.
 
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