351c exhaust manifold questions

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I am building a 71 351 4v and I am considering trying to go back with cast iron manifolds instead of headers. I know someone who has a set of 1970 351 4v exhaust manifolds for sale. Being new to Mustangs I don't know if 70 manifolds fit on a 71 engine in a 71 Mach 1? Are there significant differences that will prevent me from using them on my 71?
Also looking for advise on manifolds vs. headers. I am concerned with how do headers fit on a 71 Mach1 351c 4v with power steering and hopefully someday factory AC back on it. I would appreciate some guidance from more knowledgeable minds. I would like to end up with as stock looking engine compartment as possible. I would prefer the look of a factory intake and manifolds. Unless the headers fit well in this body with this engine and options and then i would go with aftermarket intake as long as I'm going headers to go for the day 2 look. I know that an aftermarket intake and headers will help performance but like the stock look if I can find the right manifolds. I would appreciate any guidance I can get on this.
 
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f they are 70 CLEVELAND 4V yes, The Cleveland came out in 1970. Just make sure they're not Windsor manifolds.
I have stock cast manifolds on my engine and personally, I see no need for headers unless you're into high performance stuff or racing. If you're just like me, drive on days beginning with "S", Saturday, Sunday or Sunny, you'll be fine with cast manifolds. Easier to connect the exhaust "H" pipe (or X pipe) and no dragging on the ground!!
 
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I am sure they are 351 Cleveland 4V manifolds but out of a 70 Mustang and because it was a different body style from my 71 I thought the manifolds might be different.
Looking at a listing in MustangTek, the 70 351C4V casting number should be D0AE-9430-B passenger side and D0AE-9431-B driver side. What's confusing it also lists D0AE-9431-G driver side with a 2" opening. The 71 BOSS has the same number, but with 2 1/4" opening. As for fit, I don't think that is an issue, but..............
 
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Looking at a listing in MustangTek, the 70 351C4V casting number should be D0AE-9430-B passenger side and D0AE-9431-B driver side. What's confusing it also lists D0AE-9431-G driver side with a 2" opening. The 71 BOSS has the same number, but with 2 1/4" opening. As for fit, I don't think that is an issue, but..............
thank you
 

Hemikiller

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70 and 71-73 used the same *passenger side* exhaust manifold, but a different *driver's side*.

The D0AE-G is the 70-only driver's side manifold, and the outlet points to the rear and outward.

1644886482779.png

The D1ZE-BA is the 71-73 driver's side, the outlet points downward.

1644886529379.png

The D0AE-G was never used on the 71 Boss 351, as the driver's side manifold was changed to clear the 71-up clutch linkage. The Boss used the same 4V manifold castings as the garden variety M-code, but the outlets were machined to a 2 1/4" ID.

Either way, I'd pick them up if the price is right. You could always trade off the driver's side for the more common 71-73 part. I had a 71 Cougar with a 70 M-code engine, using the 70 manifolds. The h-pipe was bent by an exhaust shop. You might be able to get away with a 1970 4V H-pipe and have it clear, as long as you're running an automatic. The exhaust pipe on a 70 manifold will not clear the 71-73 clutch linkage.
 
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70 and 71-73 used the same *passenger side* exhaust manifold, but a different *driver's side*.

The D0AE-G is the 70-only driver's side manifold, and the outlet points to the rear and outward.

View attachment 59884

The D1ZE-BA is the 71-73 driver's side, the outlet points downward.

View attachment 59885

The D0AE-G was never used on the 71 Boss 351, as the driver's side manifold was changed to clear the 71-up clutch linkage. The Boss used the same 4V manifold castings as the garden variety M-code, but the outlets were machined to a 2 1/4" ID.

Either way, I'd pick them up if the price is right. You could always trade off the driver's side for the more common 71-73 part. I had a 71 Cougar with a 70 M-code engine, using the 70 manifolds. The h-pipe was bent by an exhaust shop. You might be able to get away with a 1970 4V H-pipe and have it clear, as long as you're running an automatic. The exhaust pipe on a 70 manifold will not clear the 71-73 clutch linkage.
Thank you for all the great information!
 

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I installed Sanderson ceramic coated headers on my 72 with 351 Cleveland. They were the only ones I could find that specifically stated they would work with power steering. They are short tube.
 
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I was looking at those on Summit's website how did they fit? Do you think they could be installed on the engine and then install engine like you can with a manifold? Did you have any issues installing?
 
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70 and 71-73 used the same *passenger side* exhaust manifold, but a different *driver's side*.

The D0AE-G is the 70-only driver's side manifold, and the outlet points to the rear and outward.

View attachment 59884

The D1ZE-BA is the 71-73 driver's side, the outlet points downward.

View attachment 59885

The D0AE-G was never used on the 71 Boss 351, as the driver's side manifold was changed to clear the 71-up clutch linkage. The Boss used the same 4V manifold castings as the garden variety M-code, but the outlets were machined to a 2 1/4" ID.

Either way, I'd pick them up if the price is right. You could always trade off the driver's side for the more common 71-73 part. I had a 71 Cougar with a 70 M-code engine, using the 70 manifolds. The h-pipe was bent by an exhaust shop. You might be able to get away with a 1970 4V H-pipe and have it clear, as long as you're running an automatic. The exhaust pipe on a 70 manifold will not clear the 71-73 clutch linkage.
That's a very interesting post Hemikiller.
In my earlier reply, I did say " As for fit, I don't think that would be an issue, BUT........." There's always a "BUT"!
Also, it goes to show one can't always believe what they read. eg. MustangTek.
 

Bobby

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I was looking at those on Summit's website how did they fit? Do you think they could be installed on the engine and then install engine like you can with a manifold? Did you have any issues installing?
They fit fine. The only issue was that on the drivers side they rubbed against the engine mount. I replaced both mounts and that solved the problem. I also found out later that possibly the mounts were out of a 73 which, to my understanding, had different mounts. Those headers are small enough that I believe can be installed on the engine prior to installing the engine itself.
 

ArtBBQ

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It never ceases to amaze me at the level of expertise and knowledge on this site. Attaboys all around
 

Hemikiller

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I installed Sanderson ceramic coated headers on my 72 with 351 Cleveland. They were the only ones I could find that specifically stated they would work with power steering. They are short tube.

Lots of errors on various websites about what header does or doesn't fit, especially with 71-73s regarding power steering, which is primarily a 65-70 Mustang issue with the external assist ram. Even some of the manufacturers catalogs have incorrect or confusing information.

For 71-73s with a 351C, the *best fitting* header that I've personally used is the Hooker Competition. The latest set I bought went in without any "massaging" whatsoever. They are 6915 for 4V heads, 6921 for 2V. They are also the only header that works with the 4V head and the 71-73 clutch linkage, unless you wanted to spend big bucks. Supposedly the Hedman 88220 fit with 2V heads and a 71-73 manual trans, but I have not personally used them.


HOOKERCOMP.JPG
 
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Thanks for the info. I looked at those on the Summit website and the fitment said the ceramic part # 6915-1HKR does not fit a 71 Mustang and the painted 6915-HKR does fit. That doesn't make sense they are supposed to be the same headers only one is ceramic coated. I am going to check with Hooker directly. You said the last set went in without any massaging, were they the ceramic coated 6915-1HKR headers or the painted 6915HKR?
 

Bobby

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Lots of errors on various websites about what header does or doesn't fit, especially with 71-73s regarding power steering, which is primarily a 65-70 Mustang issue with the external assist ram. Even some of the manufacturers catalogs have incorrect or confusing information.

For 71-73s with a 351C, the *best fitting* header that I've personally used is the Hooker Competition. The latest set I bought went in without any "massaging" whatsoever. They are 6915 for 4V heads, 6921 for 2V. They are also the only header that works with the 4V head and the 71-73 clutch linkage, unless you wanted to spend big bucks. Supposedly the Hedman 88220 fit with 2V heads and a 71-73 manual trans, but I have not personally used them.


View attachment 59911
Very true! However, phone calls to the various online vendors produced very little confirmation wise. Most techies there didnt have a clue. Stagaholics was the only vendor that had usable info about the Sanderson headers. Save a lot of time and hassle....
 
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