2v intake and carb swap to 4v

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adrian351c

Member
Joined
Apr 15, 2015
Messages
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Location
California
My Car
1973 Ford Mustang Fastback.
Engine: 351 Cleveland
Transmission: C6
Project/Daily Driver.
All major parts are original.
Second owner.
So I've been wanting to swap out my 2v carb and intake for a 4v card and intake. But I have a few questions before I start a little project like that. Like, which intake is the best? Which carburetor would go with the intake the best? And is there anything I should know about a conversion like this. Now, I do want to get a functional Ram Air hood too, so the new intake manifold and carburetor setup needs to fit under the hood with some decent clearance. Any help will be greatly appreciated.

 
Little piece of advice: put a heat insulating gasket between the intake and carb. It will prevent boiling fuel issues in newer carbs.

 
On the intake you could use either a factory M code squarebore intake or an Edelbrock performer.

A Holley 1850 600 cfm VS carb will work well. If your car is an auto make sure you get one with the provision for the kickdown linkage.

 
adrian351c,

I am running the Edelbrock Performer Plus 351C for 2v cylinders heads and a Holley 750 carburetor and Ram Air in 1971 Mustang Sports roof. My 351C is not stock. For your application, I would recommend the performer 351C for the 2v heads (#2750) and a New Holley 600 CFM Carburetor. Maybe a Holley 650 CFM would be Max.

http://www.edelbrock.com/automotive/mc/manifolds/ford/performer-351.shtml

Carburetor Calculator

http://www.summitracing.com/expertadviceandnews/calcsandtools/cfm-calculator

mustanng7173

 
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The port sizes for 2V and 4V heads and manifolds are dramatically different. You will want to get a 4-barrel manifold for 2V heads, the way Mustang7173 did.

 
The port sizes for 2V and 4V heads and manifolds are dramatically different. You will want to get a 4-barrel manifold for 2V heads, the way Mustang7173 did.
The port sizes are different but this is an old school mod that does work. According to the old Ford Performance book it is worth about 25 HP.

 
adrian351c,

I am running the Edelbrock Performer Plus 351C for 2v cylinders heads and a Holley 750 carburetor and Ram Air in 1971 Mustang Sports roof. My 351C is not stock. For your application, I would recommend the performer 351C for the 2v heads (#2750) and a New Holley 600 CFM Carburetor. Maybe a Holley 650 CFM would be Max.

http://www.edelbrock.com/automotive/mc/manifolds/ford/performer-351.shtml

Carburetor Calculator

http://www.summitracing.com/expertadviceandnews/calcsandtools/cfm-calculator

mustanng7173
Is what you recommended a 4v and intake manifold? Because that's what I really want to have right now



On the intake you could use either a factory M code squarebore intake or an Edelbrock performer.

A Holley 1850 600 cfm VS carb will work well. If your car is an auto make sure you get one with the provision for the kickdown linkage.
How can I find the m code manifold? Is there anywhere specific I should look up?

Yeah c6 auto, how do I know if it has the provision?

 
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If you want a complete 4V engine you have to change the heads from your existing 2V heads to 4V heads. There are then two types of 4V heads, closed chamber (higher compression) and open chamber (lower compression for emissions on '72s and '73s). Stock American made 2V heads are open chamber. The port sizes and valves of 4V heads are larger than 2V. This article may help:

http://www.ebay.com/gds/Ford-351-Cleveland-Engines-Key-Facts-Information-/10000000001410755/g.html

The easiest way for you to get a 4-barrel carburetor on your engine is to buy an intake manifold designed for 2V heads, the way that Mustang7173 did.

 
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adrian351c,

Yes! It was designed to adapt a 4V to the 2V cylinder heads. What type of exhaust system do you have? If you have the standard single pipe exhaust system, then a standard dual exhaust with a cross over would greatly improve the performance of this add-on. Just a thought here!

mustang7173

adrian351c,

I am running the Edelbrock Performer Plus 351C for 2v cylinders heads and a Holley 750 carburetor and Ram Air in 1971 Mustang Sports roof. My 351C is not stock. For your application, I would recommend the performer 351C for the 2v heads (#2750) and a New Holley 600 CFM Carburetor. Maybe a Holley 650 CFM would be Max.

http://www.edelbrock.com/automotive/mc/manifolds/ford/performer-351.shtml

Carburetor Calculator

http://www.summitracing.com/expertadviceandnews/calcsandtools/cfm-calculator

mustanng7173
Is what you recommended a 4v and intake manifold? Because that's what I really want to have right now



On the intake you could use either a factory M code squarebore intake or an Edelbrock performer.

A Holley 1850 600 cfm VS carb will work well. If your car is an auto make sure you get one with the provision for the kickdown linkage.
How can I find the m code manifold? Is there anywhere specific I should look up?

Yeah c6 auto, how do I know if it has the provision?
 
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I did this project last summer although I don't have a ram air hood. Used the Edelbrock 2750 intake and 1406 carb. Love the results. I had already gotten the duel exhaust done.

You can see some of the before and after shots on my flickr page https://flic.kr/s/aHskdbJDee

 
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You will get better performance gains with a manifold designed to match your 2V ports, than with an M code manifold's port mismatch. Plus, the stock M code manifold is cast iron and quite heavy.

The reference to a kickdown is referring to a kickdown provision on the carburetor for Ford transmissions.

 
We are running a Holley Street Avenger 4150 style carb on top of an old school Holley Street Dominator single plane intake manifold. Pretty cool setup, but I think those old school Holley intakes are quite challenging to find.

Weiand makes the Xcelerator for 2V heads but I wouldnt be able to give you any reviews on that part.

Marco

 
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