351CJ Intake Manifold "Where are you"?


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Nov 3, 2021
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Ok, so I've first started calling around to Edelbrock, Holley and others looking for an intake for a 351CJ heads. Now remember these ports are large (2.65/1.88). My engine builder told me to find the intake that matches the Flopro gasket 1228. Well that was the Edelbrock 2665, but when it arrived the ports were not the right size. And it was hard to find this intake and now it goes back.

Anyone have an idea what intake will get the size ports I'm looking for on these CJ Heads?

If anyone needs this intake brand new you can have it for $404 plus shipping. No one has it.

My specs say that CJ heads have the same port size as the other 4V heads, which is 2.50"x1.75". I have a set of CJ heads and intake manifold in the workshop and can verify tomorrow, if nobody else chimes in tonight. I believe all of the intake gaskets are a little larger than the ports. The only aftermarket intake manifold that I know for sure that has 4V port sizes is Blue Thunder. I also have FelPro 4V intake manifold gaskets that I can set on the heads and manifold to compare the openings.

I can also compare them to the 4V closed chamber heads I have.
Offenhauser has a 5964 but I can't find the port specs anywhere on it.
That's the one I have on my car and it matches the 4V ports very well. But be aware it's a single plane. It should have a power band of 1.800 - 8.800 rpm. I have a cam with 2.000 - 6.000, a 750 CFM carb, ported 4V closed chamber heads, flat top Pistons and a 4-speed with 3.50 rear gears. So I think it does very well with this intake. I used this intake because it has stock height and I can use my ram air system. With the Air Gap and the Blue Thunder you can not right out of the box. Now you have to look at your cars specs...
The Performer 351-4V intake has slightly smaller ports than factory to help promote velocity in the ports, or that's what Edelbrock says it does. Lots of people use them on the 4V & CJ heads, which are the same port size, without issue. Even the Performer RPM Air Gap has smaller ports based on the same idea.

If you want the best of the best in dual planes, then you need to spring for the Blue Thunder, they sell on eBay around $650.
The Edelbrock Performer or the RPM Air Gap will have smaller ports that will not match your criteria. You would have to find a BOSS 351 Buddy Bar Aluminum intake or the original Ford Cast Iron intake. Problem with these is that: 1. The Buddy Bar intakes are available from time to time on eBay but you're looking at prices at $1K or better....mostly way North of 1K. 2. You can acquire an original Ford cast iron intake and the ports will match up nicely since they were designed for each other. 3. Most of these (BOSS 351 Buddy Bar and Cast Iron Ford) would require using an Autolite spread Bore carb as any other carb would not be compatible. There are a few BOSS 351 intakes that do not have the spread bore requirement. The spread bore had two large and two small round ports to fit the Autolite 4300D carb. A VERY few Buddy Bars had two rectangular ports that would allow just about any aftermarket carb to fit. I originally was doing the same to my 72. Bought the CJ heads and had them rebuilt and also bought the Ford cast iron intake and finally a re-engineered and rebuilt Autolite 4300D carb. Of course I went in a different direction mid course of my build and opted for TrickFlow heads for my 393 Stroker. I bought a Performer intake and a 1411 Edelbrock carb. So if you are interested, I have the cast Ford intake and 4300D carb if you are interested in buying it.
The perfect port match issue has been over stressed for decades, especially with 351C 4V heads. The 2665 will sign off at about 5400 RPM. If you want more than that consider the Edelbrock performer RPM or the performer RPM Air Gap. Don't worry about the port mismatch. Depending on what you want, you could use the stock 1970-1971M code intake with the primary side entry holes resized to match the secondaries. If you want to see gains, have a skilled porter do some bowl work, short side radius work, and blend the seats to the runners. Chuck
The Edelbrock Torker is another option. I think you can fit this under the hood, but not sure if you'll need a drop-housing if you have a ram air setup. These come up for sale, used, quite regularly and go for around $150.
Here's what I came up with on port sizes:
CJ Heads, Intake Ports: 2.48"x1.75"
CJ Intake Manifold Ports: 2.40"x1.66"
Shelby (Blue Thunder) Intake Manifold Ports: 2.50"x1.73"
FelPro 1228 gasket: 2.68"x1.90"