351c exhaust manifold questions

[Aus73Mach1]

I used the Sanderson headers. Both the original cast manifolds were cracked. A slight bit of massaging to clear the RHD PS box and then had them ceramic coated. Nice easy fit, no gaskets and no leaks.

 

[Hemikiller]

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?

Like I said, Summit (and others) need help on their application listings. I wish they had a "report bad information" button on their part listings.

I bought painted 6915 headers. The ceramics are the same header, just coated. You can save yourself the phone call, they fit. The application snippet I posted above is from the Hooker catalog.

 

[72XR007]

I had the 72 351CJ and wanted headers but couldn’t afford them at the time. I can’t remember but one side of the exhaust had a dog leg in the runner. I spent a little time grinding it out and it made a great difference. Never regretted it

 

[Bill Perkins]

Stick with the Ford Factory Cast Iron Exhaust Manifolds. I put Speedway Headers on my 72 Mustang 302 and took them of and went back with Ford Factory Cast Iron Exhaust Manifolds.

 

[kcmash]

I have the factory exhaust manifolds. I looked to me like the ports on the headers were smaller than the ports on the manifolds.

Things are tight enough to with power brakes, power steering, and 4 speed linkage.

 

[ArtBBQ]

So I'm curious about the installation of " long tube" headers on a 351C 4V 71 with power steering. Or it it just easier to i stall short tube? How hard is it ? I don't have lift. Is it doable with ramps, jack stands and a pretty full tool box?
My exhaust is new from the manifold back. I realize I'll have to custom fit the connection at the collector. I'm thinking about installing a electric cutout just because. is it worth the money time ? Any other customization needed?

 

[Hemikiller]

So I'm curious about the installation of " long tube" headers on a 351C 4V 71 with power steering. Or it it just easier to i stall short tube? How hard is it ? I don't have lift. Is it doable with ramps, jack stands and a pretty full tool box?
My exhaust is new from the manifold back. I realize I'll have to custom fit the connection at the collector. I'm thinking about installing a electric cutout just because. is it worth the money time ? Any other customization needed?

No issues, no clearance problems with Hooker 6915. The passenger side can go in from the top. Driver's side goes in from the bottom - didn't even have to disconnect my clutch linkage.

Only comment I have is they do not come with collectors anymore, you have to buy those separate.

The gaskets are not the old white composite material they used to include, but are more of a manifold gasket style. They didn't last long on the dyno, but they were used on a rusty 30+ year old set of 6921s from my old Cougar, as we needed to "adjust" them with a torch to clear the absorber. I used FelPro gaskets on the actual set and they sealed fine.

 

[ArtBBQ]

Ok so here's another header question for those that have done it. Right now I have a 2.5" magnflow exhaust. It's fairly loud, rumbles and the neighbors know when I fire it up. I was told by a local mechanic that it will be noticeably louder with the headers installed. I was skeptical but I don't have any reference so I'm asking you guys what you have experienced.

 

[Q1SVT]

The gaskets are not the old white composite material they used to include, but are more of a manifold gasket style. They didn't last long on the dyno, but they were used on a rusty 30+ year old set of 6921s from my old Cougar, as we needed to "adjust" them with a torch to clear the absorber. I used FelPro gaskets on the actual set and they sealed fine.

Dead soft aluminum aka Easy-to-Form Pure 1000 Series Aluminum

Clamp two together between two pieces of wood and use hole saw. Tin snips to cut outside shape.
Jegs, others sell a single 4V & 2V header flange, clamp AL** between flange and wood block and use a trim router. [yes, will need to move the clamping around as you go... can insert two wooden plugs on each end through bolt holes, glued and flush with H-Flange to hold placement with clamps]

They will never burn through

** on the flange do just one layer, two or more layers can weld together from the speed of trim router bit...

 

[71ProjectJunk]

Car will definitely be louder with headers than with manifolds. Here is a good video of the sound difference on a Camaro SS with stock manifolds and with long tube headers, everything else being the same. Car went from 103 decibels with manifolds to 116 decibels with long tube headers. That is quite a bit of a difference.

 

[ArtBBQ]

Do you think the big difference is because they eliminated the Cats?

I got a quote of 2k from my local mechanic to install the headers on my car and fab the connection at the headers. I will probably just end up doing it myself.

 

[Hemikiller]

Do you think the big difference is because they eliminated the Cats?

I got a quote of 2k from my local mechanic to install the headers on my car and fab the connection at the headers. I will probably just end up doing it myself.

Yes, removing the cats will increase the DB level significantly. They replaced them with what looks to be a high flow type, or maybe they're dummy cats. It also doesn't help that taking a reading in an enclosed space is pretty much the opposite of how it's supposed to be done. FWIW, that guy's camera work made me want to vomit.

$2K is a "don't wanna do it" price if I've ever seen one. Install the headers yourself and bring it to whomever to fab the connector pipes. It's not hard to do if you have basic hand tools. Installation can be done on jackstands. I have cribbing blocks I made from scrap 2x off cuts, which gives me about 14" of lift at the tires, so I have miles of room under the car.

 

[71ProjectJunk]

Removing the cats will definitely make a difference in sound and make it louder. I did not think that they had removed the cats, I guess I did not watch it too closely, I could have sworn the shop said they could not do it legally unless they installed cats. To me they looked like your regular high flow cats.
2K to install the headers and weld your pipes back together is nuts, Headers are usually not easy, but no way that is a 2K job. If they have never done it, it could be an all day job, but that still does not equate to 2K. Doing headers is more of a time consuming job and a hassle to do, than it is difficult. The biggest issue is just getting the front of the car high enough to get the headers in from the bottom. Usually you cannot install headers in from the top, at least one of them usually need to go in from the bottom at an angle and you need to get the car pretty high to be able to do it. Obviously this is easy for your mechanic as he has a lift, but for the average guy that does not have a lift, it is a hassle.

 

[ArtBBQ]

$2K is a "don't wanna do it" price if I've ever seen one

That's what I thought also. I've got some time until it's warm enough in michigan to drive so I'll just do it. We have a welder at work that is really good and does side work so I'll hit him up to weld the connections for me.

 

[351c1971]

A word of caution here. The 73 motor mounts and frame mounts are totally different.
Also the Prothane motor mounts are captive like the 73 but will only fit with the 2V exhaust manifolds.