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Intake manifold/ EGR delete question


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As the new owner of a 351C-4v1973 convertible, I want to add the NASA hood and working ram air. To do this, I understand I need to delete the EGR.

I started looking for a 1971 cast iron square bore intake manifold and found two versions with the same casting number. Both have the square bore, but one has a semi circular channel on the top of the manifold under the carb the other doesn’t.

I have read that the channel was a one year anomaly that will require a special gasket with stainless steel insert, to prevent exhaust gas burning through.

I thought part of the purpose of deleting EGR was to get rid of unnecessary heat warming the gas?

My question is, which manifold do I want to install, do I need a spacer (or anything else besides gaskets, nuts etc.) and what carburetor is suggested?

The car is a numbers matching very original survivor, and, since everything is bolt on, I will be saving everything that comes off, so it can easily be restored to original. I am thinking that I want to try and make any changes look as OEM as possible 

i’ve searched the forms and found a number of posts none of which completely answer these questions

Thanks 

rich

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IIRC, the 73 ram air air cleaner was a different stamping to accommodate the extra height of the EGR, and the repops are built like the 71-72 unit. 

If you get a 70-71 M-code cast iron square bore intake, you will need a different carb, as the Motorcraft 4300D used on the 71-74 Q-code was a unique spread-bore type pattern. If the car runs fine as-is, my choice would be a 71-72 Q-code intake, which doesn't have the EGR passage and retain the existing carb. This would eliminate any modifications you would need to make to vacuum systems etc. Another option would be the aluminum 71 Boss 351 intake casting # D1ZX-CA. If you don't want the carb heat passage, it's fairly simple to tap the drilled passage for a plug. 

If you do want to go with the early square bore intake, there's really no carb out there that's going to look OEM. The most "OEM-ish" thing you could do would be use a Holley dual feed carb and install the dual feed front bowl, crossover and filter to make it look like a Boss 302 carb. You'll have to make some adjustments to your vacuum lines and PCV setup. 

 

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Hemikiller

Do you have the part number for the 71-72 Q code manifold, it sounds like the easiest way to go. So  if I understand correctly, with the 71-72 Q code manifold I would simply remove the 73 manifold and egr spacer and bolt in the 70-71 manifold and re-use the original 73  spread bore 4300 carb? I will try to locate that manifold.

Any suggestions on who makes the best repro NASA hood w/ the hood lock holes? Also, from my reading of the posts, the same 351 repro ram air - air cleaner works with all the sbf engines (302, 351-2v & 351-4v)? 

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Just a heads up on re-installing the intake. There have been many posts on this, many opinions, tips and suggestions. If you have not done one before on a 351C, it's worth searching for info. Some like using a "turkey pan" other's don't. Either way don't use the rubber end strips that come with the gasket/pan kits. Not cheap, but buy a tube of "The Right Stuff" as it is way better than any RTV. Apply a 1/4" + bead along the  block ends and up the heads by about 1". Do this and you'll not have any leaks, oil or vacuum.

Geoff.

 I learn something new every day!

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I probably have an intake will have to check. I have never had an issue using the end rubber seals on the intake?? You need someone to help set it on without knocking them off. Would rather have a solid rubber seal than some RTV to seal it up. All of this went through lots of testing, hot room, cold room, 40,000 miles on test track before the launched so they worked. 

On the NASA hood I think none come with the hood lock holes you have to cut them yourself. There are some good links on the site on how to do. You work from the inside and have to make you a guide to center on the reinforcement to drill a hole for the hole saw.

When a man is in the woods and talks and no women are there is he still wrong??:P

David

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If you have an intake I'm definitely interested. I found that Dynacorn makes a ram air hood with the round lock holes already cut, any feedback about the quality of their products? I'm excited, car arrives here thursday, then I'll really know just how much work it needs 

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22 hours ago, Carolina_Mountain_Mustangs said:

I probably have an intake will have to check. I have never had an issue using the end rubber seals on the intake?? You need someone to help set it on without knocking them off. Would rather have a solid rubber seal than some RTV to seal it up. All of this went through lots of testing, hot room, cold room, 40,000 miles on test track before the launched so they worked. 

On the NASA hood I think none come with the hood lock holes you have to cut them yourself. There are some good links on the site on how to do. You work from the inside and have to make you a guide to center on the reinforcement to drill a hole for the hole saw.

David, like I said, many opinions. In this pic, you can see the rubber seal in the mirror that has failed and all the oil it puked out. "The Right Stuff", which is not RTV,  fixed it. Was it installed correctly when this motor was rebuilt in 2016, maybe, maybe not, I personally don't trust them. I'd rather not risk it due to the amount of work to fix it.

Just my opinion, nothing personal.

 

IMG_0625_LI.jpg

Geoff.

 I learn something new every day!

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On the dynacorn hood. You will have to change the arch to fit your fenders. They do not weld the inner to the outer skin so you can do that. You have to put blocks of wood on floor on all four corners and have stacks of spacers to put under the center of the hood to stop the flex. You actually stand on it be take arch out. You keep dropping your stop blocks and keep taking arch out until it matches your fenders. Takes some time for sure. On and off several time no other way to do it. When right you tack weld the inner to the outer where the hem is. Look at your old hood you will see spot welds.
Good to know that they put the holes in now. 
I have a friend that has a restoration shop. He does for GM what ever comes in. He always sands the black E-coat off the outside of the hood and many times there is rust under the E-coat. He does not sand the inside off. They sit around and rust. I have found same thing on Ford panels also. Had OEM Ford trunk and fender I sanded down recently had rust under the primer. 

On the rubber end seals I have never changed them on my 73 that I bought new so they will work if done right.

 

When a man is in the woods and talks and no women are there is he still wrong??:P

David

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I fought end gaskets on intake manifolds for years, tried cork and rubber gaskets and every gasket sealer (regular RTV was the worse) I could think of and probably half of them leaked on a variety of engines (FEs, Y block valley covers, small blocks, etc). I even tried grooving and dimpling the mating surfaces to give the gaskets something to grip to. Then a guy at the parts counter at the local Ford dealer told me about the TA Motorcraft gasket maker 30 years or so ago. I never used gaskets on the ends of the intake manifolds, valley covers, or on differentials and on other items again. And then they came out with Right Stuff, easier to get and a little cheaper. I haven't had an end seal leak again, nor around differential covers or carriers.

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