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where can i get an adapter to put a 4bbl carb on my 351 instead of haveing the 2bbl thats already on it. i checked mr. gasket but thay have a 2bbl to 4bbl adapter. can you flip it over and use it?
thanks Tim
 

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wind & fire = guides to power
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Why not run a 500CFM Ford or Holley 2bbl? It would have better flow charecteristics than an inverted 2/4 adapter. Why you might even get more total flow than a 600cfm on a 2/4 adapter.
 

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current hot rod: CTS-V
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Fordy8man said:
where can i get an adapter to put a 4bbl carb on my 351 instead of haveing the 2bbl thats already on it. i checked mr. gasket but thay have a 2bbl to 4bbl adapter. can you flip it over and use it?
thanks Tim
I would put the money towards a correct intake manifold, but wouldn't a 2bbl to 4bbl adapter be just what you need to go from your 2bbl to a 4bbl?
 

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4 bbl to 2 bbl

I dont recommend running an adaptor that allows running a 4 bbl carb on a 2 bbl manifold. An alternative is to run a 500 Holley 2 bbl but be warned your fuel consumption will go up significantly. I have done this with both 302's and 351's and my mileage dropped off as much as 25%. That being said, there was a noticeable improvement on the mid range and top end power. You can purchase a small 4 bbl carb (500 -600 cfm) for the price of the 500 2 bbl.
IF your desire it to run a 4 bbl, you should go ahead and invest in an old factory or aftermarket 4 bbl intake. If you are going to be running this on a stock engine, go with a Performer or Weiand Action series intake. For the cost, you could well find a factory Ho unit from a 351 HO from the 80's.
Ford also made factory 4 bbl intakes for the 351 W in 69 and 70, and put them in cars. I have a factory 69 351 W intake sitting on a parts shelf in my garage.
Be advised that there are basically two versions of the factory 4 bbl intake. The 69-70 version have 8 bolts per side where all the aftermarket and later versions had 6 bolts per side.
To run the 8 bolt version on a later engine, you will need to plug # 2 and 7 bolt holes in the intake, or you will wind up with water spraying all over the place, as the bosses for these two bolts on each side was built into the water outlets.
Its a simple matter of plugging them and there are two ways to do it. Either tap the holes and put in set screws with plenty of sealer on them. Do not tap the hole all the way through. The other alternative is to install small freeze plugs in the holes(easiest).

One other thing, the 2 bbl manifold isnt designed to flow the kind of air your 4 bbl will breath.
Second other thing, 2 bbl carbs are rated at 3"hg while 4 bbls are rated at 1.5"hg. To find the compareable flow of a 2 bbl as a 4 bbl, you will need to divide the 2 bbl cfm rate by 1.4.
IE a 500 2 bbl would be rated as a 357 cfm carb.
 
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