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| Cad 500 GMC Headers [message #152849] |
Tue, 13 December 2011 18:53  |
djeffers
Messages: 219
Registered: June 2004
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Hello all,
We would like to hear from those that have installed and used Cad 500 Headers in their GMC.
We dug into our Cad 500 to replace the broken right side exhaust manifold and discovered the left side exhaust manifold (the hard to get ElDorado one) is cracked and is on it's way to breaking into two pieces as well. Our replacement right side manifold looks good.
So what do you think of your Cad 500 headers; where did you get them and anything eles you can say about them to help us decide what to do? Buy headers or replace the ElDorado manifold?
We are debating whether to try to find a good left side ElDorado exhaust manifold or install a set of headers.
Thanks,
Don & Susan Jeffers
78 Eleganza II
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| Re: Cad 500 GMC Headers [message #152854 is a reply to message #152849] |
Tue, 13 December 2011 19:10  |
Larry
Messages: 2875
Registered: January 2004
Location: Menomonie, WI
Karma: 10
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I think that the only one making them is "The Cad Company" of Albuquerque. Ask for the headers that are made for the GMCMH. They are specially made for the Cad 500 in a GMCMH and curl up high enough on the drivers side so that you can get the transmission governor out without having to unbolt the header. Last time I talked to them, they had two versions of the headers...a set that are mandrel bent, and a set that are bent using a standard tube bender. I have a set, but have not installed yet because my manifolds are still in good condition. Keep in mind, IIRC, when you install these headers, they may not be a direct replacement. You may have to change the pipes coming off of them as they do not terminate in the same place that the old manifolds did. You may want to ask them about that before you buy.
| djeffers wrote on Tue, 13 December 2011 18:53 |
Hello all,
We would like to hear from those that have installed and used Cad 500 Headers in their GMC.
We dug into our Cad 500 to replace the broken right side exhaust manifold and discovered the left side exhaust manifold (the hard to get ElDorado one) is cracked and is on it's way to breaking into two pieces as well. Our replacement right side manifold looks good.
So what do you think of your Cad 500 headers; where did you get them and anything eles you can say about them to help us decide what to do? Buy headers or replace the ElDorado manifold?
We are debating whether to try to find a good left side ElDorado exhaust manifold or install a set of headers.
Thanks,
Don & Susan Jeffers
78 Eleganza II
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Larry 
78 Royale w/500 Caddy
Menomonie, WI.
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| Re: Cad 500 GMC Headers [message #152858 is a reply to message #152857] |
Tue, 13 December 2011 19:24 |
Larry
Messages: 2875
Registered: January 2004
Location: Menomonie, WI
Karma: 10
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Senior Member |
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| djeffers wrote on Tue, 13 December 2011 19:14 |
Larry,
Did you spring for the mandrel bent or get the standard tube bender edition? I'm wondering how good or bad the tube bender version look. Obviously the mandrel bent should look better.
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At the time, I had sent a little business to him, and then he failed to show for a presentation that I arranged at the WS balloon rally in Albuquerque. So he gave me a hell of a deal on a carry out set of standard tube benders. They look OK, but looks aren't everything...it's how they perform, and since I have not installed, i can't comment on that. Here is this pic taken by Russ Harms of a Mandrel set.
http://www.gmcmhphotos.com/photos/showphoto.php?photo=7216&cat=3476
Larry
78 Royale w/500 Caddy
Menomonie, WI.
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| Re: [GMCnet] Cad 500 GMC Headers [message #152873 is a reply to message #152858] |
Tue, 13 December 2011 20:56 |
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USAussie
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
Karma: 6
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Larry,
When you get some time it would be helpful if you could post some pictures of the standard tube bender headers so we can compare
them to Russ's mandrel bent headers.
I've got a spare set of cast iron manifolds for the Caddy here in Sydney.
Regards,
Rob M.
-----Original Message-----
From: Larry
At the time, I had sent a little business to him, and then he failed to show for a presentation that I arranged at the WS balloon
rally in Albuquerque. So he gave me a hell of a deal on a carry out set of standard tube benders. They look OK, but looks aren't
everything...it's how they perform, and since I have not installed, i can't comment on that. Here is this pic taken by Russ Harms
of a Mandrel set.
http://www.gmcmhphotos.com/photos/showphoto.php?photo=7216&cat=3476
--
Larry
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Regards,
Rob M. (USAussie)
The Pedantic Mechanic
Sydney, Australia
'75 Avion - AUS - The Blue Streak TZE365V100428
'75 Avion - USA - Double Trouble TZE365V100426
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| Re: [GMCnet] Cad 500 GMC Headers [message #152884 is a reply to message #152858] |
Tue, 13 December 2011 21:41 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
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Senior Member |
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I don't like the looks of those flanges a-tall! Surely they've corrected
that by now though. Am I confused, or is the "heat shield" on the top of
the L. header, while the governor is underneath?
I'm anxious to hear the experiences also, since I've got leaks at the
manifold-exhaust pipe joints and fear that my solutions may result in
cracking the manifolds. Any suggestions for curing those leaks greatly
appreciated before I do help decimate the manifold population.
Ken H.
Americus, GA
'76 X-Birchaven w/Cad500/Howell EFI+ & EBL
www.gmcwipersetc.com
On Tue, Dec 13, 2011 at 8:24 PM, Larry wrote:
>
>
> djeffers wrote on Tue, 13 December 2011 19:14
> > Larry,
> >
> > Did you spring for the mandrel bent or get the standard tube bender
> edition? I'm wondering how good or bad the tube bender version look.
> Obviously the mandrel bent should look better.
>
> At the time, I had sent a little business to him, and then he failed to
> show for a presentation that I arranged at the WS balloon rally in
> Albuquerque. So he gave me a hell of a deal on a carry out set of standard
> tube benders. They look OK, but looks aren't everything...it's how they
> perform, and since I have not installed, i can't comment on that. Here is
> this pic taken by Russ Harms of a Mandrel set.
>
> http://www.gmcmhphotos.com/photos/showphoto.php?photo=7216&cat=3476
> --
>
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Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
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| Re: Cad 500 GMC Headers [message #152898 is a reply to message #152849] |
Tue, 13 December 2011 22:23 |
djeffers
Messages: 219
Registered: June 2004
Karma: 2
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Senior Member |
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I called the Cad Co today about their headers for the Cad 500 GMC Motorhome.
Their headers don't include the reducers (transition pipes) or the down pipes. You are left to your own devices for these items. They had no photos of either their mandrel bend or the tubing bender headers. They have the header jigs set up and when they get an order they have a welder made up.
So that’s why I was asking the GMC community about their experience with headers. At this point I am in repair mode and will probably replace my other broken exhaust manifold, the left side, rather than get into making transitions and down pipes.
And I, too, was a little baffled by the heat shield? on the left side Cad Co header.
Does anyone have a good left side ElDorado exhaust manifold for sale?
I can make my own headers, but it is a lot more time and effort than replacing an exhaust manifold.
It would be considerably less effort to convert the Olds/GMC headers to the Cad 500 than making a set of Cad headers from scratch. Perhaps a project for warmer weather as I am presently in the north land, working outside.
Does anyone have a set of Olds GMC headers for sale?.
I also have some things to say about the Cad exhaust manifold breakage problems, but I will start a new thread for that subject.
Don & Susan Jeffers
78 Eleganza II
Cad 500 factory EFI
[Updated on: Tue, 13 December 2011 22:26] Report message to a moderator |
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| Re: [GMCnet] Cad 500 GMC Headers [message #152900 is a reply to message #152898] |
Tue, 13 December 2011 22:29 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
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Senior Member |
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Don,
Kosier will probably reply with something similar to this, since he has the
pieces in hand: I've always heard that the easiest route is to modify
Chevy 454 headers to fit Cad flanges. I think Cad Co offers those flanges.
Ken H.
On Tue, Dec 13, 2011 at 11:23 PM, Don Jeffers wrote:
> ...
> I can make my own headers, but it is a lot more time and effort than
> replacing an exhaust manifold.
>
> It would be considerably less effort to convert the Olds/GMC headers to
> the Cad 500 than making a set of Cad headers from scratch. Perhaps a
> project for warmer weather as I am presently in the north land, working
> outside.
> ...
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www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
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| Re: [GMCnet] Cad 500 GMC Headers [message #152908 is a reply to message #152898] |
Tue, 13 December 2011 23:32 |
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USAussie
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
Karma: 6
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Senior Member |
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Don,
To make sure you get the correct side please confirm:
Left = Driver Side
Right = Passenger Side
Unfortunately the driver side is the hard side to find because they were unique to FWD Eldorado.
I do a daily search for "Cadillac 500 parts" and it has taken me a year to find two driver side exhaust manifolds that were in good
shape that the seller didn't want the moon for.
The basic shape of the ports on an Olds 455 are WAY different from a Caddy 500, I reckon it would be a real bear to make them fit
especially since the Olds has Siamese center ports.
Here's a link to a guy selling what appears to be good quality header flanges.
http://www.ebay.com/itm/Big-Block-Cadillac-425-472-500-Exhaust-Header-Flange-/270853392549?pt=Motors_Car_Truck_Parts_Accessories&vxp
=mtr&hash=item3f101ec8a5
Regards,
Rob M.
-----Original Message-----
From: gmclist-bounces@temp.gmcnet.org [mailto:gmclist-bounces@temp.gmcnet.org] On Behalf Of Don Jeffers

I called the Cad Co today about their headers for the Cad 500 GMC Motorhome.
Their headers don't include the reducers (transition pipes) or the down pipes. You are left to your own devices for these items.
They had no photos of either their mandrel bend or the tubing bender headers. They have the header jigs set up and when they get an
order they have a welder made up.
So that’s why I was asking the GMC community about their experience with headers. At this point I am in repair mode and will
probably replace my other broken exhaust manifold, the left side, rather than get into making transitions and down pipes.
Does anyone have a good left side ElDorado exhaust manifold for sale?
I can make my own headers, but it is a lot more time and effort than replacing an exhaust manifold.
It would be considerably less effort to convert the Olds/GMC headers to the Cad 500 than making a set of Cad headers from scratch.
Perhaps a project for warmer weather as I am presently in the north land, working outside.
Does anyone have a set of Olds GMC headers for sale?.
I also have some things to say about the Cad exhaust manifold breakage problems, but I will start a new thread for that subject.
Don
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Regards,
Rob M. (USAussie)
The Pedantic Mechanic
Sydney, Australia
'75 Avion - AUS - The Blue Streak TZE365V100428
'75 Avion - USA - Double Trouble TZE365V100426
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| Re: Cad 500 GMC Headers [message #152925 is a reply to message #152898] |
Wed, 14 December 2011 09:34 |
Larry
Messages: 2875
Registered: January 2004
Location: Menomonie, WI
Karma: 10
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Senior Member |
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| djeffers wrote on Tue, 13 December 2011 22:23 |
I called the Cad Co today about their headers for the Cad 500 GMC Motorhome.
Their headers don't include the reducers (transition pipes) or the down pipes. You are left to your own devices for these items. They had no photos of either their mandrel bend or the tubing bender headers. They have the header jigs set up and when they get an order they have a welder made up.
So that’s why I was asking the GMC community about their experience with headers. At this point I am in repair mode and will probably replace my other broken exhaust manifold, the left side, rather than get into making transitions and down pipes.
And I, too, was a little baffled by the heat shield? on the left side Cad Co header.
Does anyone have a good left side ElDorado exhaust manifold for sale?
I can make my own headers, but it is a lot more time and effort than replacing an exhaust manifold.
It would be considerably less effort to convert the Olds/GMC headers to the Cad 500 than making a set of Cad headers from scratch. Perhaps a project for warmer weather as I am presently in the north land, working outside.
Does anyone have a set of Olds GMC headers for sale?.
I also have some things to say about the Cad exhaust manifold breakage problems, but I will start a new thread for that subject.
Don & Susan Jeffers
78 Eleganza II
Cad 500 factory EFI
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We had a person that was a member of GMCMI and WS that was the first person to install headers from the Cad Company. In fact he worked with the Cad Co on the design of the header. He then installed them on his GMCMH Cad 500 and ran them for a while. My CRS is working hard today keeping me from remembering his name, but I remember that he drives a 78' Royale and tows a VW dune buggy. Anyone remember who that is?
I'll try to dig those headers out today and take a photo of them.
Larry
78 Royale w/500 Caddy
Menomonie, WI.
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| Re: Cad 500 GMC Headers [message #152929 is a reply to message #152925] |
Wed, 14 December 2011 09:56 |
Bob de Kruyff
Messages: 4260
Registered: January 2004
Location: Chandler, AZ
Karma: 1
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""We had a person that was a member of GMCMI and WS that was the first person to install headers from the Cad Company. In fact he worked with the Cad Co on the design of the header. He then installed them on his GMCMH Cad 500 and ran them for a while. My CRS is working hard today keeping me from remembering his name, but I remember that he drives a 78' Royale and tows a VW dune buggy. Anyone remember who that is?
I'll try to dig those headers out today and take a photo of them. ""
Was it Jim Wagner?
Bob de Kruyff
78 Eleganza
Chandler, AZ
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| Re: Cad 500 GMC Headers [message #152954 is a reply to message #152950] |
Wed, 14 December 2011 15:50 |
Larry
Messages: 2875
Registered: January 2004
Location: Menomonie, WI
Karma: 10
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Senior Member |
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| Jim Wagner wrote on Wed, 14 December 2011 14:53 |
Larry,
Are you thinking of Milt Wade? I think he is from Las Vegas. I have the Caddy exhaust flanges but haven't found a bbc header to use. Since we use the Corvette as a rear pusher the headers are not high on our list.:>)
Jim Wagner
Brook Park, oh
Was it Jim Wagner?
No, Jim is not the person that I was thinking of, but Jim may be running headers...I don't know. Been thinking about this all morning, and I think either his first or last name was Wade.....Anyone??
--------------------------------------------------------------------------------
Larry
78 Royale w/500 Caddy
Menomonie, WI.
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Yup!!! Milt Wade is the one. Thanks Jim. Don, you may want to contact Milt Wade. He should be in the GMCMI or WS roster. He could tell you a little about his header experiences.
Jim...Wagner...do you have headers?
Larry
78 Royale w/500 Caddy
Menomonie, WI.
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| Re: [GMCnet] Cad 500 GMC Headers [message #152979 is a reply to message #152945] |
Wed, 14 December 2011 19:20 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
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Senior Member |
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Don,
No, I haven't tried "real" Eldorado flares; I'll have to try to find some;
that is the cause of my problems, I'm sure -- too small flares.
Thanks,
Ken H.
On Wed, Dec 14, 2011 at 3:03 PM, Don Jeffers wrote:
> ... Have you tried GM ElDorado down pipes with their GM flares?
>
>
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www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
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| Re: [GMCnet] Cad 500 GMC Headers [message #152988 is a reply to message #152979] |
Wed, 14 December 2011 21:02 |
Kosier
Messages: 834
Registered: February 2008
Karma: 1
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Senior Member |
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Ken,
It needs to be a "ball flare". I couldn't find anyone that could
make one,
so I used the first few inches of the Eldo pipe. At 2&1/4" It
just nicely
slipped inside a piece of 2&1/2" pipe. Easy weld job.
Gary Kosier
----- Original Message -----
From: "Ken Henderson" <hend4800@bellsouth.net>
To: <gmclist@temp.gmcnet.org>
Sent: Wednesday, December 14, 2011 8:20 PM
Subject: Re: [GMCnet] Cad 500 GMC Headers
> Don,
>
> No, I haven't tried "real" Eldorado flares; I'll have to try to
> find some;
> that is the cause of my problems, I'm sure -- too small flares.
>
> Thanks,
>
> Ken H.
>
>
> On Wed, Dec 14, 2011 at 3:03 PM, Don Jeffers wrote:
>
>> ... Have you tried GM ElDorado down pipes with their GM
>> flares?
>>
>>
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| Re: [GMCnet] Cad 500 GMC Headers [message #152989 is a reply to message #152988] |
Wed, 14 December 2011 21:09 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
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Senior Member |
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Thanks, Gary. Now to find 2.
KenH
On Wed, Dec 14, 2011 at 10:02 PM, Kosier wrote:
> Ken,
>
> It needs to be a "ball flare". I couldn't find anyone that could
> make one,
> so I used the first few inches of the Eldo pipe. At 2&1/4" It
> just nicely
> slipped inside a piece of 2&1/2" pipe. Easy weld job.
>
>
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Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
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