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Re: [GMCnet] Cracked intake [message #63611] Mon, 09 November 2009 17:04 Go to next message
chip is currently offline  chip   United States
Messages: 37
Registered: November 2009
Karma: -2
Member


Thanks Rob. Sounds like the Dick Paterson gaskets / block off's
should take care of me.

Appreciate the info / help !

Chip

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On Mon 09/11/09 1:25 PM , "Rob Mueller" robmueller@iinet.net.au
sent:
Chip,
I used Mr. Gasket fiber intake gaskets P/N 404 when I installed the
aluminum
intake manifold made by Gary Rockwell which does not have a
crossover.
Had I known that the Edelbrock 7284 was available I would have used
that
gasket because it has a Nitrile bead around the ports and the steel
core
which would provide more protection to the aluminum manifold where
it meets
the crossover ports in the heads than the Mr. Gasket fiber gaskets.
If I
ever had to remove the intake I would use the Edelbrock 7284 when I
re-installed it.
I have never seen the Edelbrock gasket and therefore can only assume
that
Summit is correct stating that the 7284 is correct for the 455. I
did check
the Edelbrock website and it notes the same thing.
I doubt that the steel core would be adequate to block off the
crossover
(for very long) because it probably is pretty thin. I did have a set
of Dick
Paterson gaskets with stainless steel block off plates and I would
GUESS
that they were around 0.40 thick. I decided that the Mr. Gasket
fiber
gaskets would be OK to use with the Rockwell manifold. Only time and
mileage
will tell if I was correct or not!
Here's a link to Dick Paterson's gaskets and block off plates:
http://www.springfield-ignition.com/blockoff.htm [1]
BTW you can easily see the difference in the port height between a
455 and a
403 in the photo!
Regards,
Rob Mueller
Sydney, Australia
AUS '75 Avion-The Blue Streak TZE365V100428
USA '75 Avion-Double Trouble TZE365V100426
-----Original Message-----
From: gmclist-bounces@temp.gmcnet.org [2]
[gmclist-bounces@temp.gmcnet.org [3]] On Behalf Of chip@mach3isp.com
Sent: Tuesday, 10 November 2009 7:07 AM
To: gmclist@temp.gmcnet.org [4]
Subject: Re: [GMCnet] Cracked intake
Rob:
Are you saying these are the correct gaskets for a 455? And they
will be adequate to block off the heat crossover without filling it
in ?
Please advise, am new to this and in the process of pulling my 455
for
rebuild.
Thanks - Chip
1977 Clasco
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Links:
------
[1] http://www.springfield-ignition.com/blockoff.htm
[2] mailto:gmclist-bounces@temp.gmcnet.org
[3] mailto:gmclist-bounces@temp.gmcnet.org
[4] mailto:gmclist@temp.gmcnet.org
[5] http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
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Re: [GMCnet] Cracked intake [message #63617 is a reply to message #63611] Mon, 09 November 2009 17:38 Go to previous messageGo to next message
USAussie is currently offline  USAussie   United States
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
Karma: 6
Senior Member
Chip,

On a final note I would HIGHLY recommend that when you do decide to block
the crossovers that you do it when you have plenty of time to figure out
what you want to address the problem if you find it cracked.

You have a number of options if you find your manifold cracked:

1) Weld repair the cracks
Comment: will it really seal properly and how long will it last?
2) Find a replacement manifold
Comment: If you get one off another GMC it probably is also cracked!
Try to find one off a Toronado.
3) Install an aluminum manifold from Edelbrock
Comment: their manifold is higher and you will have to build a dog
house on the engine cover for the carb / air cleaner to fit into.
4) Install an aluminum manifold from Gary Rockwell
Comment: they cost $600!

I am of the opinion that at this point in time a great majority of GMC's
that don't have the crossover blocked have cracked intake manifolds but the
owners don't know it!

Rob Mueller
Sydney, Australia
AUS '75 Avion-The Blue Streak TZE365V100428
USA '75 Avion-Double Trouble TZE365V100426


-----Original Message-----
From: gmclist-bounces@temp.gmcnet.org
[mailto:gmclist-bounces@temp.gmcnet.org] On Behalf Of chip@mach3isp.com
Sent: Tuesday, 10 November 2009 10:04 AM
To: gmclist@temp.gmcnet.org
Subject: Re: [GMCnet] Cracked intake

Thanks Rob. Sounds like the Dick Paterson gaskets / block off's
should take care of me.

Appreciate the info / help !

Chip

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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
Re: [GMCnet] Cracked intake [message #63619 is a reply to message #63617] Mon, 09 November 2009 17:49 Go to previous messageGo to next message
Mike Kilroy is currently offline  Mike Kilroy   United States
Messages: 80
Registered: July 2006
Location: Farmersville, OH (near D...
Karma: 0
Member
One last idea Chip: if you block and/or fill the crossovers, you will
wonder what to do with your choke. Most opt to replace it with an
electric one but that has its own issues. I kept mine original and it
still works fine - just takes a tad longer to open fully but no issue to
me. and no mods needed.

On 11/9/2009 6:38 PM, Rob Mueller wrote:
> Chip,
>
> On a final note I would HIGHLY recommend that when you do decide to block
> the crossovers that you do it when you have plenty of time to figure out
> what you want to address the problem if you find it cracked.
>
> You have a number of options if you find your manifold cracked:

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Mike (AC8V) & Vickie Kilroy
'73 Canyon Land 26' sidebath
455/ceramic filled crossovers
Re: [GMCnet] Cracked intake [message #65213 is a reply to message #63619] Sat, 21 November 2009 17:55 Go to previous messageGo to next message
Terry Skinner is currently offline  Terry Skinner   United States
Messages: 379
Registered: January 2004
Karma: 0
Senior Member
Some have used a piece of quarter inch copper tubing to wrapped around
the exhaust pipe and back up to the carburetor. Works..........Terry

On Mon, Nov 9, 2009 at 3:49 PM, Mike Kilroy <mike@kilroywashere.com> wrote:
> One last idea Chip:  if you block and/or fill the crossovers, you will
> wonder what to do with your choke.  Most opt to replace it with an
> electric one but that has its own issues.  I kept mine original and it
> still works fine - just takes a tad longer to open fully but no issue to
> me.  and no mods needed.
>
> On 11/9/2009 6:38 PM, Rob Mueller wrote:
>> Chip,
>>
>> On a final note I would HIGHLY recommend that when you do decide to block
>> the crossovers that you do it when you have plenty of time to figure out
>> what you want to address the problem if you find it cracked.
>>
>> You have a number of options if you find your manifold cracked:
>
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>



--
Terry Skinner
253-686-2624
Roy. Washington
'76 GMC
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Re: [GMCnet] Cracked intake [message #65217 is a reply to message #65213] Sat, 21 November 2009 18:38 Go to previous message
WD0AFQ is currently offline  WD0AFQ   United States
Messages: 7111
Registered: November 2004
Location: Dexter, Mo.
Karma: 207
Senior Member
Terry Skinner wrote on Sat, 21 November 2009 17:55

Some have used a piece of quarter inch copper tubing to wrapped around
the exhaust pipe and back up to the carburetor. Works..........Terry




--
Terry Skinner
253-686-2624
Roy. Washington
'76 GMC
_______________________________________________







Terry, that is what I did on my Mustang for the choke. Then I bought an electric one and ended all problems.
Dan


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