Home » Public Forums » GMCnet » New aluminum intake manifold, anything to watch out for?
| New aluminum intake manifold, anything to watch out for? [message #302774] |
Tue, 28 June 2016 14:41  |
lw8000
Messages: 201
Registered: July 2012
Location: S.E. Michigan
Karma: 1
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As I mentioned in another post we recently found our original intake manifold on our 403 has the crack starting and is about halfway through. Based on what I read here, it appears the only options for a new intake are aluminum, made by Rockwell and Edelbrock. I called Cinnabar today and they have the Edelbrock aluminum manifold and include the "turkey tray" with it as well. They mentioned it is raised about 3/8" above where the OEM one is so I will have to check to make sure we are good (they mentioned that it should be OK as long as the body pads are in good shape).
Going with aluminum, is there any downside or anything to watch out for? Are the aluminum ones less prone to crack like the original? I thought I had read once the green ethylene glycol antifreeze could potentially eat away aluminum but is that really an issue? Any other plusses or minuses? Maybe we're stuck going with this as I'm guessing finding a cast iron manifold means going with a used one... and I'd rather do this once and do it right and not have to worry about it ever again.
Thanks much, in advance....,
--
Chris
Chris S. -
77 Kingsley, 3.70 FD, mostly OEM -
S.E. Michigan
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| Re: [GMCnet] New aluminum intake manifold, anything to watch out for? [message #302775 is a reply to message #302774] |
Tue, 28 June 2016 15:01  |
Keith V
Messages: 2337
Registered: March 2008
Location: Mounds View,MN
Karma: 0
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Is the Rockwell intake no longer available?
It's a bolt in replacement IIRC with the crossovers blocked.
My understanding is the Edelbrock intake flows too much for our low RPM and you loose low end torque
>
> As I mentioned in another post we recently found our original intake manifold on our 403 has the crack starting and is about halfway through. Based
> on what I read here, it appears the only options for a new intake are aluminum, made by Rockwell and Edelbrock. I called Cinnabar today and they have
> the Edelbrock aluminum manifold and include the "turkey tray" with it as well. They mentioned it is raised about 3/8" above where the OEM one is so I
> will have to check to make sure we are good (they mentioned that it should be OK as long as the body pads are in good shape).
>
> Going with aluminum, is there any downside or anything to watch out for? Are the aluminum ones less prone to crack like the original? I thought I
> had read once the green ethylene glycol antifreeze could potentially eat away aluminum but is that really an issue? Any other plusses or minuses?
> Maybe we're stuck going with this as I'm guessing finding a cast iron manifold means going with a used one... and I'd rather do this once and do it
> right and not have to worry about it ever again.
>
> Thanks much, in advance....,
> --
> Chris
> --
> Chris S. -
> 77 Kingsley mostly OEM -
> S.E. Michigan
>
> _______________________________________________
> GMCnet mailing list
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Keith Vasilakes
Mounds View. MN
75 ex Royale GMC
ask me about MicroLevel
Cell, 763-732-3419
My427v8@hotmail.com
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| Re: New aluminum intake manifold, anything to watch out for? [message #302777 is a reply to message #302774] |
Tue, 28 June 2016 15:18 |
lqqkatjon
Messages: 2324
Registered: October 2010
Location: St. Cloud, MN
Karma: 5
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have heard of people who had a difficult time getting the rockwell to install/seal. But I do not know the whole story, if it was install error, or a problem with the casting.
I am sure there are some good original intakes out there, and if they test good, and the cross over is blocked, you should have good service life.
I am not sure I would worry about the corrosion factor of the aluminum intake.... I can't imagine that being a problem.
applied is showing a new one on there website as well, and I see some special gasket stuff that is supposed to go with it??
have seen a few edlebrock intakes, but none where they did not have to raise the floor a small amount.
Jon Roche
75 palm beach
EBL EFI, manny headers, Micro Level, rebuilt most of coach now.
St. Cloud, MN
http://lqqkatjon.blogspot.com/
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| Re: New aluminum intake manifold, anything to watch out for? [message #302778 is a reply to message #302774] |
Tue, 28 June 2016 15:32 |
Chris Tyler
Messages: 458
Registered: September 2013
Location: Odessa FL
Karma: 7
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I had a performer [not RPM] and was planning to swap. The difference is more than 3/8, i would say more like 3/3 to 1" compared to stock. Its hard to tell without having them both off.
I spolke with them on the phone regarding the power curve. Their testing doesnt really go below 3000rpm. However, they felt the low end torque would be about the same perhaps very slightly higher due to better velocity. They also said it would make more in the midrange and top end. The manifold design is for off idle to 5500 but most of us never will exceed 4000-4500.
They also said the older edelbrock manifold [C4B? not sure] is a bit lower if you can find one
In the end decided it wasnt worth doing as a stand alone mod.
76 Glenbrook
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| Re: New aluminum intake manifold, anything to watch out for? [message #302779 is a reply to message #302774] |
Tue, 28 June 2016 15:41 |
C Boyd
Messages: 2629
Registered: April 2006
Karma: 18
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Sir, the 403 is a small block Olds and any 350 intake will fit. Don't have to be off a toro.Weiand makes a low rise street aluminum I believe. The aluminum Rockwell is for the big block 455 that does need the low Toro type intake to keep from hitting the floor.
lw8000 wrote on Tue, 28 June 2016 15:41As I mentioned in another post we recently found our original intake manifold on our 403 has the crack starting and is about halfway through. Based on what I read here, it appears the only options for a new intake are aluminum, made by Rockwell and Edelbrock. I called Cinnabar today and they have the Edelbrock aluminum manifold and include the "turkey tray" with it as well. They mentioned it is raised about 3/8" above where the OEM one is so I will have to check to make sure we are good (they mentioned that it should be OK as long as the body pads are in good shape).
Going with aluminum, is there any downside or anything to watch out for? Are the aluminum ones less prone to crack like the original? I thought I had read once the green ethylene glycol antifreeze could potentially eat away aluminum but is that really an issue? Any other plusses or minuses? Maybe we're stuck going with this as I'm guessing finding a cast iron manifold means going with a used one... and I'd rather do this once and do it right and not have to worry about it ever again.
Thanks much, in advance....,
--
Chris
C. Boyd
76 Crestmont
East Tennessee
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| Re: [GMCnet] New aluminum intake manifold, anything to watch out for? [message #302780 is a reply to message #302775] |
Tue, 28 June 2016 15:39 |
James Hupy
Messages: 6806
Registered: May 2010
Karma: -62
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The Rockwell manifold is for the 455. The Edelbrock Performer is for the
403. The deck height on the 403 is low enough that the air cleaner clears
the engine hatch when using the stock air cleaner. The hatch will NOT CLEAR
when you use an Edelbrock Performer on a 455. The Rockwell WILL CLEAR.
Alignment of gaskets, manifold, and head passages on the 455 is critical
when fitting the Rockwell. Bottom end performance when using the Edelbrock
manifold is not adversely affected on the 403. I have done it several
times. If ethylene glycol anti freeze is changed before the corrosion
inhibitors become ineffective, no electrolysis problems should be
encountered with an aluminum manifold. Edelbrock will give a data sheet
warning about blocking crossover passages on oldsmobile engines. Some
GMCer, it might have been Emery or Ken H. encountered a problem using their
block off plugs. I don't remember exact details. Perhaps they can chime in
here.
Jim Hupy
Salem, Or
78 GMC ROYALE 403
On Jun 28, 2016 1:02 PM, "Keith V" wrote:
> Is the Rockwell intake no longer available?
> It's a bolt in replacement IIRC with the crossovers blocked.
>
> My understanding is the Edelbrock intake flows too much for our low RPM
> and you loose low end torque
>
>>
>> As I mentioned in another post we recently found our original intake
> manifold on our 403 has the crack starting and is about halfway through.
> Based
>> on what I read here, it appears the only options for a new intake are
> aluminum, made by Rockwell and Edelbrock. I called Cinnabar today and they
> have
>> the Edelbrock aluminum manifold and include the "turkey tray" with it as
> well. They mentioned it is raised about 3/8" above where the OEM one is so
> I
>> will have to check to make sure we are good (they mentioned that it
> should be OK as long as the body pads are in good shape).
>>
>> Going with aluminum, is there any downside or anything to watch out
> for? Are the aluminum ones less prone to crack like the original? I
> thought I
>> had read once the green ethylene glycol antifreeze could potentially eat
> away aluminum but is that really an issue? Any other plusses or minuses?
>> Maybe we're stuck going with this as I'm guessing finding a cast iron
> manifold means going with a used one... and I'd rather do this once and do
> it
>> right and not have to worry about it ever again.
>>
>> Thanks much, in advance....,
>> --
>> Chris
>> --
>> Chris S. -
>> 77 Kingsley mostly OEM -
>> S.E. Michigan
>>
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
> _______________________________________________
> GMCnet mailing list
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| Re: [GMCnet] New aluminum intake manifold, anything to watch out for? [message #302782 is a reply to message #302779] |
Tue, 28 June 2016 15:49 |
Keith V
Messages: 2337
Registered: March 2008
Location: Mounds View,MN
Karma: 0
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Senior Member |
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Oh, opps, Nevermind.
>
> Sir, the 403 is a small block Olds and any 350 intake will fit. Don't have to be off a toro.Weiand makes a low rise street aluminum I believe. The
> aluminum Rockwell is for the big block 455 that does need the low Toro type intake to keep from hitting the floor.
>
>
> lw8000 wrote on Tue, 28 June 2016 15:41
>> As I mentioned in another post we recently found our original intake manifold on our 403 has the crack starting and is about halfway through.
>> Based on what I read here, it appears the only options for a new intake are aluminum, made by Rockwell and Edelbrock. I called Cinnabar today and
>> they have the Edelbrock aluminum manifold and include the "turkey tray" with it as well. They mentioned it is raised about 3/8" above where the OEM
>> one is so I will have to check to make sure we are good (they mentioned that it should be OK as long as the body pads are in good shape).
>>
>> Going with aluminum, is there any downside or anything to watch out for? Are the aluminum ones less prone to crack like the original? I thought
>> I had read once the green ethylene glycol antifreeze could potentially eat away aluminum but is that really an issue? Any other plusses or minuses?
>> Maybe we're stuck going with this as I'm guessing finding a cast iron manifold means going with a used one... and I'd rather do this once and do it
>> right and not have to worry about it ever again.
>>
>> Thanks much, in advance....,
>> --
>> Chris
>
>
> --
> C. Boyd
> 76 Crestmont
> East Tennessee
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
_______________________________________________
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Keith Vasilakes
Mounds View. MN
75 ex Royale GMC
ask me about MicroLevel
Cell, 763-732-3419
My427v8@hotmail.com
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| Re: [GMCnet] New aluminum intake manifold, anything to watch out for? [message #302787 is a reply to message #302774] |
Tue, 28 June 2016 17:00 |
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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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Chris,
Save yourself a lot of money by:
1) Purchasing a set of these gaskets: http://www.springfield-ignition.com/gmc-motorhome/block-off-kits/
Regards,
Rob M.
USAussie - Downunder
AUS '75 Avion - The Blue Streak TZE365V100428
USA '75 Avion - Double Trouble TZE365V100426
-----Original Message-----
From: Gmclist [mailto:gmclist-bounces@list.gmcnet.org] On Behalf Of Chris S.
Sent: Wednesday, June 29, 2016 5:41 AM
To: gmclist@list.gmcnet.org
Subject: [GMCnet] New aluminum intake manifold, anything to watch out for?
As I mentioned in another post we recently found our original intake manifold on our 403 has the crack starting and is about halfway
through. Based
on what I read here, it appears the only options for a new intake are aluminum, made by Rockwell and Edelbrock. I called Cinnabar
today and they have
the Edelbrock aluminum manifold and include the "turkey tray" with it as well. They mentioned it is raised about 3/8" above where
the OEM one is so I
will have to check to make sure we are good (they mentioned that it should be OK as long as the body pads are in good shape).
Going with aluminum, is there any downside or anything to watch out for? Are the aluminum ones less prone to crack like the
original? I thought I
had read once the green ethylene glycol antifreeze could potentially eat away aluminum but is that really an issue? Any other
plusses or minuses?
Maybe we're stuck going with this as I'm guessing finding a cast iron manifold means going with a used one... and I'd rather do this
once and do it
right and not have to worry about it ever again.
Thanks much, in advance....,
--
Chris
--
Chris S. -
77 Kingsley mostly OEM -
S.E. Michigan
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
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Unsubscribe or Change List Options:
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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] New aluminum intake manifold, anything to watch out for? [message #302790 is a reply to message #302774] |
Tue, 28 June 2016 17:20 |
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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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Chris,
I accidently sent my previous reply before it was complete.
Save yourself a lot of money by:
1) Remove your OEM intake.
2) Buy a set of these gaskets: http://www.springfield-ignition.com/gmc-motorhome/block-off-kits/
3) Buy a small tube of:
https://www.permatex.com/products/gasketing/gasket-makers/permatex-high-temp-red-rtv-silicone-gasket/
4) Fill the crack(s) in your OEM manifold with high temp RTV.
5) Re-install the repaired OEM manifold.
Once the exhaust crossover(s) are blocked the temperature in the crossover will track the temperature of the oil vapors in the
lifter valley, probably around 200°F vs. 1200°F with them open. At two hundred degrees the crack(s) in the manifold will not open up
and cause any problems especially since you have sealed them.
Regards,
Rob M.
USAussie - Downunder
AUS '75 Avion - The Blue Streak TZE365V100428
USA '75 Avion - Double Trouble TZE365V100426
-----Original Message-----
From: Gmclist [mailto:gmclist-bounces@list.gmcnet.org] On Behalf Of Chris S.
Sent: Wednesday, June 29, 2016 5:41 AM
To: gmclist@list.gmcnet.org
Subject: [GMCnet] New aluminum intake manifold, anything to watch out for?
As I mentioned in another post we recently found our original intake manifold on our 403 has the crack starting and is about halfway
through. Based on what I read here, it appears the only options for a new intake are aluminum, made by Rockwell and Edelbrock. I
called Cinnabar today and they have the Edelbrock aluminum manifold and include the "turkey tray" with it as well. They mentioned
it is raised about 3/8" above where the OEM one is so I will have to check to make sure we are good (they mentioned that it should
be OK as long as the body pads are in good shape).
Going with aluminum, is there any downside or anything to watch out for? Are the aluminum ones less prone to crack like the
original? I thought I had read once the green ethylene glycol antifreeze could potentially eat away aluminum but is that really an
issue? Any other plusses or minuses?
Maybe we're stuck going with this as I'm guessing finding a cast iron manifold means going with a used one... and I'd rather do this
once and do it right and not have to worry about it ever again.
Thanks much, in advance....,
--
Chris
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
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] New aluminum intake manifold, anything to watch out for? [message #302791 is a reply to message #302788] |
Tue, 28 June 2016 17:20 |
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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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A,
Look closer and you will see that Dick makes a kit for BOTH the 455 and 403.
Regards,
Rob M.
USAussie - Downunder
AUS '75 Avion - The Blue Streak TZE365V100428
USA '75 Avion - Double Trouble TZE365V100426
-----Original Message-----
From: Gmclist [mailto:gmclist-bounces@list.gmcnet.org] On Behalf Of A.
Sent: Wednesday, June 29, 2016 8:08 AM
To: gmclist@list.gmcnet.org
Subject: Re: [GMCnet] New aluminum intake manifold,anything to watch out for?
USAussie wrote on Tue, 28 June 2016 17:00
> Chris,
> Save yourself a lot of money by:
>
> 1) Purchasing a set of these gaskets: http://www.springfield-ignition.com/gmc-motorhome/block-off-kits/
>
>
> Regards,
> Rob M.
> USAussie - Downunder
> AUS '75 Avion - The Blue Streak TZE365V100428
> USA '75 Avion - Double Trouble TZE365V100426
That looks like a kit for a 455. This thread is about a 403 (which I didn't know EVEN had problems with the intake manifold
cracking...).
--
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GMCnet mailing list
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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] New aluminum intake manifold, anything to watch out for? [message #302803 is a reply to message #302796] |
Tue, 28 June 2016 22:11 |
jimk
Messages: 6734
Registered: July 2006
Location: Belmont, CA
Karma: 9
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Senior Member |
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We stock the Aluminum intake for both 403 and 455.
We also stock the Springfield intake with block off plates for both.
On Tue, Jun 28, 2016 at 5:40 PM, Chris S. wrote:
> Thanks all for the wealth of info on this one and for the offers on parts,
> too. I will consider all of the options and see which way we decide to go
> on this. It sounds like there is really no right or wrong way, which is
> good to know :) As always, thanks again for all of your help.
> --
> Chris S. -
> 77 Kingsley mostly OEM -
> S.E. Michigan
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
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>
--
Jim Kanomata
Applied/GMC, Fremont,CA
jimk@appliedairfilters.com
http://www.appliedgmc.com
1-800-752-7502
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Jim Kanomata
Applied/GMC
jimk@appliedairfilters.com
www.appliedgmc.com
1-800-752-7502
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| Re: [GMCnet] New aluminum intake manifold, anything to watch out for? [message #302811 is a reply to message #302803] |
Wed, 29 June 2016 07:53 |
lw8000
Messages: 201
Registered: July 2012
Location: S.E. Michigan
Karma: 1
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Senior Member |
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jimk wrote on Tue, 28 June 2016 22:11We stock the Aluminum intake for both 403 and 455.
We also stock the Springfield intake with block off plates for both.
Jim,
What exactly is the Springfield intake? I had not heard or seen this one yet.
Thank you!
Chris S. -
77 Kingsley, 3.70 FD, mostly OEM -
S.E. Michigan
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| Re: [GMCnet] New aluminum intake manifold, anything to watch out for? [message #302819 is a reply to message #302811] |
Wed, 29 June 2016 08:56 |
jimk
Messages: 6734
Registered: July 2006
Location: Belmont, CA
Karma: 9
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Senior Member |
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You can go to our sight www.appliedgmc.com and under engine, youll see the
gaskets.
Nothing more than a fiber gasket with a slot cut out to accept a SS plate
that you place over the exhaust crossover.
If I'm not mistaken, the 403 al. intakes dont need the plate, as they are
blocked off.
On Wed, Jun 29, 2016 at 5:53 AM, Chris S. wrote:
> jimk wrote on Tue, 28 June 2016 22:11
>> We stock the Aluminum intake for both 403 and 455.
>> We also stock the Springfield intake with block off plates for both.
>
>
> Jim,
> What exactly is the Springfield intake? I had not heard or seen this one
> yet.
> Thank you!
> --
> Chris S. -
> 77 Kingsley mostly OEM -
> S.E. Michigan
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
--
Jim Kanomata
Applied/GMC, Fremont,CA
jimk@appliedairfilters.com
http://www.appliedgmc.com
1-800-752-7502
_______________________________________________
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Jim Kanomata
Applied/GMC
jimk@appliedairfilters.com
www.appliedgmc.com
1-800-752-7502
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As always, thanks again for all of your help.