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| [GMCnet] Caddy 500 Headers [message #234050] |
Thu, 26 December 2013 18:40  |
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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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G'day,
I'm doing a bit of research and would like to know:
1) Who has headers on their Caddy 500 powered GMC?
2) Where were they purchased?
3) How much were they?
4) Did they have to make any modifications to make them fit?
5) Can you get the transmission governor out without removing the driver side?
AFAIK The Cad Co in Albuquerque, NM is the only company that makes headers for the Caddy?
http://www.cad500parts.com/catalog/page30.htm
Quote
GMC Motorhomes (FWD) (mandrel bent) $795
GMC Motorhomes (FWD) (non-mandrel bent) $595
These fit in most Cadillac engine swaps into the 70s Olds-powered GMC FWD Motor Homes.
Designed for use with our bolt-in motor mount kit, but for other swaps as well.
These headers are hand built, and Mig welded, not mass produced.
If your transmission dipstick tube support bracket uses an exhaust manifold bolt, you will have to modify the bracket to fit.
Unquote
Regards,
Rob M.
Sydney, Australia
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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] Caddy 500 Headers [message #234055 is a reply to message #234050] |
Thu, 26 December 2013 19:34  |
cbryan
Messages: 451
Registered: May 2012
Location: Ennis, Texas
Karma: 3
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Senior Member |
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Rob,
Those are all I have heard of. I am thinking four into two into one headers might be worthwhile to suppress detonation. See Mazda Skyactiv technology. 13-1 compression ration on pump gas.
Carey Bryan
Carey from Ennis, Texas
78 Royale, 500 Cadillac, Rance Baxter EFI.
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| Re: [GMCnet] Caddy 500 Headers [message #234061 is a reply to message #234050] |
Thu, 26 December 2013 20:08 |
kerry pinkerton
Messages: 2565
Registered: July 2012
Location: Harvest, Al
Karma: 15
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Senior Member |
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It would be interesting to get one of the engine guys to chime in on this but I have to wonder if a 500 CI Caddy (or a 455 Olds) at 4000 RPM gets any measurable benefit from headers over the OEM manifolds?
Kerry Pinkerton - North Alabama
Had 5 over the years. Currently have a '06 Fleetwood Discovery 39L
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| Re: [GMCnet] Caddy 500 Headers [message #234083 is a reply to message #234050] |
Thu, 26 December 2013 23:00 |
Larry
Messages: 2875
Registered: January 2004
Location: Menomonie, WI
Karma: 10
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Senior Member |
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| Robert Mueller wrote on Thu, 26 December 2013 18:40 |
G'day,
I'm doing a bit of research and would like to know:
1) Who has headers on their Caddy 500 powered GMC?
2) Where were they purchased?
3) How much were they?
4) Did they have to make any modifications to make them fit?
5) Can you get the transmission governor out without removing the driver side?
AFAIK The Cad Co in Albuquerque, NM is the only company that makes headers for the Caddy?
http://www.cad500parts.com/catalog/page30.htm
Quote
GMC Motorhomes (FWD) (mandrel bent) $795
GMC Motorhomes (FWD) (non-mandrel bent) $595
These fit in most Cadillac engine swaps into the 70s Olds-powered GMC FWD Motor Homes.
Designed for use with our bolt-in motor mount kit, but for other swaps as well.
These headers are hand built, and Mig welded, not mass produced.
If your transmission dipstick tube support bracket uses an exhaust manifold bolt, you will have to modify the bracket to fit.
Unquote
Regards,
Rob M.
Sydney, Australia
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Cad Co's headers were originally designed in cooperation with a GMC'r (who's name I'm failing to remember). But he made sure during the design portion that they were bent in such a way as to allow removal of the governor without having to pull the left header. I have a set of non-mandrel bent headers that I bought from them 9 yrs ago. Never got a chance to install them. They were IIRC $250 at that time. Given the RPM that we run at, IMO, the stock cast Iron manifolds (if you can find a set that are not cracked) are quite adequate. JWIT
Larry 
78 Royale w/500 Caddy
Menomonie, WI.
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| Re: [GMCnet] Caddy 500 Headers [message #234105 is a reply to message #234055] |
Fri, 27 December 2013 07:48 |
mrgmc3
Messages: 210
Registered: September 2013
Location: W Washington
Karma: 2
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Senior Member |
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| cbryan wrote on Thu, 26 December 2013 19:34 |
Rob,
Those are all I have heard of. I am thinking four into two into one headers might be worthwhile to suppress detonation. See Mazda Skyactiv technology. 13-1 compression ration on pump gas.
Carey Bryan
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The enablers of high compression in new engines like Mazda are provided by aluminum heads, variable valve timing, and high pressure direct injection relative to our old cast iron two valve motors.
The most practical steps to reduce detonation on these V8s would be;
- outside air induction
- good radiator cooling (210F max)
- port injection (cools incoming charge)
- cam profiles that reduce peak cyl pressure (but they also reduce peak torque - not really what you want in an RV)
- aluminum heads (but there is also a torque loss here - due to heat loss - I'll probably get a fight over this one - but in a previous life we compared aluminum to cast iron, all else being equal for cyl heads. You could run 1 point higher CR but at a 3% loss in torque - heat loss - so there was no net gain other than weight savings)
30 years of engine technology have given us faster burn chambers, variable valve timing, and direct injection. All pretty hard to adapt to the Caddy or Olds V8
Chris Geils - Twin Cities / W Wa
1978 26' Kingsley w/ very few mods; PD9040, aux trans cooler, one repaint in stock colors, R134a, Al rad, Alcoas, 54k mi
[Updated on: Fri, 27 December 2013 07:49] Report message to a moderator |
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| Re: [GMCnet] Caddy 500 Headers [message #234169 is a reply to message #234134] |
Fri, 27 December 2013 17:32 |
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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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Anthony,
Thanks, however, there seems to be a problem, note the following:
Here's a copy of the ad out of their catalog specials:
Mandrel Bent Mid-Length Headers - $400
Cad Company's mass produced mid-length headers are available to fit a variety of vehicles. Don't settle for one-size-fits-none,
flanges that won't seal, and lack-luster performance. These headers feature cnc mandrel bent 1 3/4" thick-wall primaries, 3"
collectors with 3-bolt flanges, 3/8" thick main flanges (surfaced after finish welding), and are jig-built and TiG welded for a
consistant fit and reliable performance for years to come. We have these headers in stock to fit the following vehicles:
- '68-'76 RWD Cadillac (Deville, Fleetwood, etc)
- '68-'78 Eldorado
- '77-'85 RWD Cadillac (with 472/500/425 engines)
- '73-'91 (square body) Chevy/GMC Trucks
- '88-'95 Chevy/GMC Trucks
- '70-'81 F-Body (Firebird and Camaro)
- '78-'87 G-Body (Malibu, Monte Carlo, Cutlass, Regal, El Camino, Etc)
We are currently offering a package deal for the Holiday season. Order online now, and receive our exclusive premium headers,
composite header gaskets, and a set of standard black 12-point header bolts, as well as free shipping in the 48 states, for the
unbeatable price of $400. If your order will be shipped outside of the 48 states, we will send you a notification with shipping
total via PayPal.
Header kit
Headers - gaskets - bolts - Free 48 State Shipping
Online-only price: $400
Note that these are NOT listed (nor are they in the pull down list):
GMC Motorhomes (FWD) (mandrel bent) $795
GMC Motorhomes (FWD) (non-mandrel bent) $595
These fit in most Cadillac engine swaps into the 70s Olds-powered GMC FWD Motor Homes.
Designed for use with our bolt-in motor mount kit, but fir other swaps as well.
These headers are hand built, and Mig welded, not mass produced.
If your transmission dipstick tube support bracket uses an exhaust manifold bolt, you will have to modify the bracket to fit.
I just called (4:30 PM Mountain Time) but there was no answer, I suspect they're closed until Monday.
Regards,
Rob M.
Sydney, Australia
-----Original Message-----
From: anthony ezzo
cad500parts.com specials tab
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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] Caddy 500 Headers [message #234180 is a reply to message #234169] |
Fri, 27 December 2013 18:20 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
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Senior Member |
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Since we successfully use Eldorado OEM manifolds, I wonder why Cadco's
Eldorado headers won't work? Especially after hearing that their GMC
manifolds require different exhaust pipes than the manifolds. Since we
already have those exhaust pipes, why bother with making new ones for their
GMC-unique headers?
Just wonderin',
Rob, I learned during my recent purchase of a complete valve train from
them that their telephone monitoring stinks. At least half of my calls
reached an answering machine. Of the other half, at least half reached a
non-knowledge phone-answerer. The remaining 25% (probably closer to 10%)
were answered by knowledgeable, helpful, individuals -- usually Chris.
Ken H.
On Fri, Dec 27, 2013 at 6:32 PM, Robert Mueller <robmueller@iinet.net.au>wrote:
> ...
> Note that these are NOT listed (nor are they in the pull down list):
>
> GMC Motorhomes (FWD) (mandrel bent) $795
> GMC Motorhomes (FWD) (non-mandrel bent) $595
> These fit in most Cadillac engine swaps into the 70s Olds-powered GMC FWD
> Motor Homes.
> Designed for use with our bolt-in motor mount kit, but fir other swaps as
> well.
> ...
>
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Unsubscribe or Change List Options:
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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: [GMCnet] Caddy 500 Headers [message #234182 is a reply to message #234180] |
Fri, 27 December 2013 18:38 |
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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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Ken,
The downpipes would have to be located to clear the transmission; however, I suspect the collectors and outlet flanges to connect to
the rest of the exhaust system would not be in the same place.
Regards,
Rob M.
Sydney, Australia
-----Original Message-----
From: gmclist-bounces@temp.gmcnet.org [mailto:gmclist-bounces@temp.gmcnet.org] On Behalf Of Ken Henderson
Sent: Saturday, December 28, 2013 11:20 AM
To: gmclist
Subject: Re: [GMCnet] Caddy 500 Headers
Since we successfully use Eldorado OEM manifolds, I wonder why Cadco's
Eldorado headers won't work? Especially after hearing that their GMC
manifolds require different exhaust pipes than the manifolds. Since we
already have those exhaust pipes, why bother with making new ones for their
GMC-unique headers?
Just wonderin',
Rob, I learned during my recent purchase of a complete valve train from
them that their telephone monitoring stinks. At least half of my calls
reached an answering machine. Of the other half, at least half reached a
non-knowledge phone-answerer. The remaining 25% (probably closer to 10%)
were answered by knowledgeable, helpful, individuals -- usually Chris.
Ken H.
On Fri, Dec 27, 2013 at 6:32 PM, Robert Mueller <robmueller@iinet.net.au>wrote:
> ...
> Note that these are NOT listed (nor are they in the pull down list):
>
> GMC Motorhomes (FWD) (mandrel bent) $795
> GMC Motorhomes (FWD) (non-mandrel bent) $595
> These fit in most Cadillac engine swaps into the 70s Olds-powered GMC FWD
> Motor Homes.
> Designed for use with our bolt-in motor mount kit, but fir other swaps as
> well.
> ...
>
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
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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