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Interesting findings on Hedman 4x4 headers

April 15 2017 at 10:57 AM

Ross  (Login Bad427stang)
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I am doing some work to my 445 and saw where the gasket imprint was a little odd on the header gaskets.

When I got to looking close, 89180 Hedmans for 69-76 360/390 F100s (odd range of years) don't really match up perfectly to anything, except maybe an unmolested C6AE-R

The exhaust port floor of my D2TE-AA heads is approx .110 lower than it should be to match the headers, and a CJ/Edelbrock exhaust port is approx .070 too high.

Not that this is an extreme problem LOL but it begs the question, if you have to drop the header by .110 to make a real nice port match for the D2TE-AA heads, OR, you have to raise the header by .070 to make a good match for the early heads, what did they make the headers to fit originally?

If the application was early 352 it would make sense for a C6AE-R, but 69-76 would be C8AE-H or D2TE-AA

Anyway, looks like a decent justification to make some changes happy.gif
[linked image]
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- 70 Fastback Mustang, 489 cid FE, Victor, SEFI, TKO-600 5 speed, 4.11 9 inch.
- 71 F100 shortbed 4x4, 445 cid FE, headers, RPM intake, 1000 HP series Holley, 4 speed

 
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Anonymous
(Login BBFTorino)
Members

What ya gonna do??

April 15 2017, 11:05 AM 

Are you going to cut the flanges off and re-center them, or something similar??

 
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Ross
(Login Bad427stang)
Members

On the fence

April 15 2017, 11:10 AM 

Toying with the idea of aluminum heads and just dressing the bolt holes to raise the headers. Downside is that the iron heads flow a bit more than a stock set of Edels will. Upside is that it is the easiest route and likely makes it a little less fussy on fuel

Another upside is that I have another little rowdy 390 coming together, it may get a bit rowdier if I give it the good ported iron heads happy.gif
[linked image]
---------------------------------
- 70 Fastback Mustang, 489 cid FE, Victor, SEFI, TKO-600 5 speed, 4.11 9 inch.
- 71 F100 shortbed 4x4, 445 cid FE, headers, RPM intake, 1000 HP series Holley, 4 speed

 
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Marc K
(Login mdkallas)
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Re: Interesting findings on Hedman 4x4 headers

April 15 2017, 3:25 PM 

I have the same heads and headers and my heads happen to be removed at the moment. The headman gasket matches perfect to the bottom of the D2 exhaust port on mine.
Maybe your port has been cut lower?

 
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Ross
(Login Bad427stang)
Members

The gasket matches perfect, it's the header

April 15 2017, 4:55 PM 

My gaskets match the heads, and I have both Hedman and Hooker truck gaskets here, same thing, it's the headers that are slightly higher. In fact, if I flip the gaket upside down, the D2 gaskets are a closer match to the header

It's not a lot, less than an 1/8 of an inch and I never had a leak, but it it very close to not holding a gasket on one tube due to slight manufacturing difference at the weld ring
[linked image]
---------------------------------
- 70 Fastback Mustang, 489 cid FE, Victor, SEFI, TKO-600 5 speed, 4.11 9 inch.
- 71 F100 shortbed 4x4, 445 cid FE, headers, RPM intake, 1000 HP series Holley, 4 speed

 
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TorinoBP88
(Login TorinoBP88)
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"CJ/Edelbrock exhaust port is approx .070 too high. "

April 19 2017, 12:00 PM 

The head port a little higher can help the flow buy helping the turn down, and help stop some of the reversion if there is a shock wave returning up the exhaust pipe. But Ross i'm sure your pipes are big and flow like a storm sewer so not much back pressure on your truck, LOL!

Interesting findings, probably one of those compromises when they wanted to appeal to as many customers as possible.

 
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