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Carb Options For Offy Dual Plane on 240

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Carb Options For Offy Dual Plane on 240

Post #1 by Red72FarmTruck » Thu Oct 03, 2019 3:12 pm

So motor should be ready in a few weeks. I've purchased an Offy Dual Plane for my 240. It going to be getting a slightly overstock cam (RV style). I'm looking for suggestions on carbs. I have seen many running bigger 2 barrels to small four barrels. Are there big modifications that have to be made to the linkage when going this route? Anyone have a preference on basic smaller 4 barrel?

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Re: Carb Options For Offy Dual Plane on 240

Post #2 by MechRick » Thu Oct 03, 2019 6:55 pm

Location matters. I had problems here in Vegas with a Carter 500 cfm four barrel, heat causing fuel to vaporize out of the bowls (heat soak). If you are in a cooler climate they work well though.

Holley 8007 390 cfm is a bolt on and go solution, but they are pricey.

Cheaper route is a vacuum secondary Holley 600, but it may take some tuning on the Offy DP to get it to run right.

You do need to run a non-synchronous (progressive linkage) carb on the DP to take advantage of the smaller runners in the intake (MPG), so most two barrels are out.
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Re: Carb Options For Offy Dual Plane on 240

Post #3 by guhfluh » Thu Oct 03, 2019 7:07 pm

Anything is going to take some decent reworking of the factory linkage on a 72 to work sideways on a Dual Port manifold. What may work the best is a conversion to cable from a late 70's truck or something from Lokar that might convert the stock linkage.
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Re: Carb Options For Offy Dual Plane on 240

Post #4 by F-250 Restorer » Fri Oct 04, 2019 8:08 pm

I am in So.Cal and had the same heat issue with a DP and a Summit 600 carb. I now use a Holley, and don't have any heat problems. Just for clarification, I only had the problem during hot summer days.
My truck is a 75. When I installed the DP and 4v carb, I converted to a Locar 48" cable. It was very easy to install.

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Re: Carb Options For Offy Dual Plane on 240

Post #5 by old28racer » Sat Oct 05, 2019 11:27 am

What Holley carb are you using with the DP intake manifold? I am in Southern CA.
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