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[GMCnet] 455 Intake Manifolds [message #274599] Mon, 30 March 2015 16:40 Go to next message
USAussie is currently offline  USAussie   United States
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Registered: July 2007
Location: Sydney, Australia
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Senior Member
G'day,

Before I returned to Sydney I took the three intake manifolds for a 455 GMC I have in Houston took some measurements I thought might
be helpful:

I turned them over on my workbench and sat them on the carb mounting surface then measured the distance from the workbench to the
front lifter valley sealing surface and the rear lifter valley sealing surface.

OEM Manifold

Front: 3.55 inches
Rear: 3.77 inches

Edelbrock Performer

Front: 4.50 inches
Rear: 5.60 inches

Edelbrock Performer that has had the carb mounting surface milled down reducing the height.

Front: 3.76 inches
Rear: 4.08 inches

The depth of the plenum under the carb mounting surface is about the same as the OEM manifold.

Regards,
Rob M.
The Pedantic Mechanic
USAussie - Downunder


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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] 455 Intake Manifolds [message #274607 is a reply to message #274599] Mon, 30 March 2015 18:48 Go to previous messageGo to next message
Harry is currently offline  Harry   Canada
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Has anyone used the Edelbrock manifold that has been milled?
Does the engine cover fit correctly?
Re: [GMCnet] 455 Intake Manifolds [message #274609 is a reply to message #274607] Mon, 30 March 2015 20:29 Go to previous messageGo to next message
USAussie is currently offline  USAussie   United States
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David,

If you compare the dimensions of that manifold to the OEM manifold you'll see that you still need to raise the engine cover.

Regards,
Rob M.

-----Original Message-----
From: Gmclist [mailto:gmclist-bounces@temp.gmcnet.org] On Behalf Of David H. Jarvis
Sent: Tuesday, March 31, 2015 10:49 AM
To: gmclist@temp.gmcnet.org
Subject: Re: [GMCnet] 455 Intake Manifolds

Has anyone used the Edelbrock manifold that has been milled?
Does the engine cover fit correctly?
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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] 455 Intake Manifolds [message #274661 is a reply to message #274599] Tue, 31 March 2015 12:46 Go to previous messageGo to next message
bwevers is currently offline  bwevers   United States
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Only 1/4 " higher after milling? And it still won't fit.

Bill Wevers GMC49ers, GMC Western States 1975 Glenbrook - Manny Powerdrive, OneTon 455 F Block, G heads San Jose
Re: [GMCnet] 455 Intake Manifolds [message #274664 is a reply to message #274661] Tue, 31 March 2015 14:21 Go to previous messageGo to next message
Bob de Kruyff   United States
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bwevers wrote on Tue, 31 March 2015 11:46
Only 1/4 " higher after milling? And it still won't fit.

I don't know how close the air cleaners are to the underside of the hatch cover by design but it must be very close. I know my 403 lightly rubs on the hatch and wonder how bad it will be when I replace the front mount. I suspect the 455 is similar.


Bob de Kruyff
78 Eleganza
Chandler, AZ
Re: [GMCnet] 455 Intake Manifolds [message #274668 is a reply to message #274664] Tue, 31 March 2015 14:25 Go to previous messageGo to next message
James Hupy is currently offline  James Hupy   United States
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More than likely a case of middle age sag in the body to frame mounting
pads, as well as the body itself. Kinda like me I guess. ( grin)
Jim Hupy
Salem, Or
78 GMC ROYALE 403
On Mar 31, 2015 12:21 PM, "Bob de Kruyff" wrote:

> bwevers wrote on Tue, 31 March 2015 11:46
>> Only 1/4 " higher after milling? And it still won't fit.
>
> I don't know how close the air cleaners are to the underside of the hatch
> cover by design but it must be very close. I know my 403 lightly rubs on the
> hatch and wonder how bad it will be when I replace the front mount. I
> suspect the 455 is similar.
> --
> Bob de Kruyff
> 78 Eleganza
> Chandler, AZ
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
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Re: [GMCnet] 455 Intake Manifolds [message #274674 is a reply to message #274668] Tue, 31 March 2015 15:44 Go to previous messageGo to next message
Bob de Kruyff   United States
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Registered: January 2004
Location: Chandler, AZ
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James Hupy wrote on Tue, 31 March 2015 13:25
More than likely a case of middle age sag in the body to frame mounting
pads, as well as the body itself. Kinda like me I guess. ( grin)
Jim Hupy
Salem, Or
78 GMC ROYALE 403
On Mar 31, 2015 12:21 PM, "Bob de Kruyff" wrote:

> bwevers wrote on Tue, 31 March 2015 11:46
>> Only 1/4 " higher after milling? And it still won't fit.
>
> I don't know how close the air cleaners are to the underside of the hatch
> cover by design but it must be very close. I know my 403 lightly rubs on the
> hatch and wonder how bad it will be when I replace the front mount. I
> suspect the 455 is similar.
> --
> Bob de Kruyff
> 78 Eleganza
> Chandler, AZ
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
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I agree that is part of the issue. I do wonder however what the initial design clearance was--I bet it was on the edge of wetness.


Bob de Kruyff
78 Eleganza
Chandler, AZ
Re: [GMCnet] 455 Intake Manifolds [message #274679 is a reply to message #274661] Tue, 31 March 2015 16:27 Go to previous message
USAussie is currently offline  USAussie   United States
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
Karma: 6
Senior Member
Bill,

I did not have this manifold milled down I got it with a bunch of parts I bought from a fellow GMCer, I have NOT installed it.

It would be IRRESPONSIBLE for me to say it would fit when I DON'T really know.

I have seen the bottom side of engine covers on some GMC's that have had the first layer or two of the plywood removed for air
cleaner clearance.

Let's say someone buys one of the Performers for $319.00 from Jegs:

http://www.jegs.com/i/Edelbrock/350/2151/10002/-1

They spend another $100 or so to have it milled.

They spend another $40 or so on gaskets.

They spend the day doing the R&R.

When they are finished they go to install the engine cover and it hits the air cleaner!

They're going to say "I just spent a day installing this bloody manifold and over $450 and it doesn't fit; why did that asshat
Mueller say it fit!"

I did notice something about this manifold I didn't mention in my earlier email and that is the plenum under the carb is about the
same depth as the OEM manifold. I did not measure it.

Unfortunately I can't answer any questions about this manifold as it is in Houston, Texas and I am in Sydney, Australia. I will be
back there in the fall so stay tuned to this channel as I intend to install it then.

Regards,
Rob M.
The Pedantic Mechanic

-----Original Message-----
From: Bill Wevers

Only 1/4 " higher after milling? And it still won't fit.

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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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