| [GMCnet] Intake Manifolds 455 and 403 [message #257401] |
Fri, 01 August 2014 00:09  |
John Brandstetter
Messages: 3
Registered: July 2014
Karma: 0
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Junior Member |
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I keep looking for info but it seems hit and miss.
Blocking Cross over is this a must and it also seems hit or miss some people say plugs come out and damage engine.
I have seen 3 types Air Gap, RPM and Tork. but no one seems to say what they do.
If you go to EFI is it better to have the Square mount and is that a reason to change intake?
1. Why change the manifold? (Weight is that only reason?)
2. Edelbrock 2151 why is this better or not better than stock
3. Rockwell seems expensive for the same thing as stock but lighter
4. Mondello (This on has no crossover)
5. Pro Comp Cheaper and looks like Mondello (crosswind)
6. Offenhauser Port O Sonic
Does anyone know anything about these or have ratings on them performance over stock etc.
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| Re: [GMCnet] Intake Manifolds 455 and 403 [message #257404 is a reply to message #257401] |
Fri, 01 August 2014 00:30  |
jimk
Messages: 6734
Registered: July 2006
Location: Belmont, CA
Karma: 9
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Senior Member |
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John,
You have lot of questions, I would like to explain them much easily via
phone.
Please call me 800-752-7502.
We work only on GMC MH so we are exposed lot of issues, plus we have
constant communication with those that are specialists in certain phase of
the coach.
Beeing 71 years old and having played with these for 35 years has given me
exposier.
On Thu, Jul 31, 2014 at 10:09 PM, John Brandstetter
wrote:
> I keep looking for info but it seems hit and miss.
>
> Blocking Cross over is this a must and it also seems hit or miss some
> people say plugs come out and damage engine.
>
> I have seen 3 types Air Gap, RPM and Tork. but no one seems to say what
> they do.
>
> If you go to EFI is it better to have the Square mount and is that a
> reason to change intake?
>
>
>
> 1. Why change the manifold? (Weight is that only reason?)
> 2. Edelbrock 2151 why is this better or not better than stock
> 3. Rockwell seems expensive for the same thing as stock but lighter
> 4. Mondello (This on has no crossover)
> 5. Pro Comp Cheaper and looks like Mondello (crosswind)
> 6. Offenhauser Port O Sonic
>
> Does anyone know anything about these or have ratings on them performance
> over stock etc.
>
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
--
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] Intake Manifolds 455 and 403 [message #257420 is a reply to message #257401] |
Fri, 01 August 2014 07:48 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
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Senior Member |
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John,
I wasn't even aware of some of the options you list, but I do have some
valid comments:
First, DO NOT install cast iron plugs in the exhaust ports in the heads,
regardless of what Edelbrock or anyone else tells you. This is not the
only verified incident of damage from that practice, nor the worst:
http://www.gmcmhphotos.com/photos/g3057-cylinder-head-damage-from-exhaust-crossover-plugs.html
http://goo.gl/GBrtC
As far as blocking the crossover, unless you live in a VERY cold climate
and intend to stay there, you'll want to block the crossover to eliminate
the excessive heating of the carburetor and everything under the hatch.
Pouring metal into the manifold as we used to do is not necessary in most
cases: blocking plates at the head/manifold joint are adequate.
All manifolds of which I am aware, except for OEM and Rockwell, are higher
than the OEM and require the engine hatch to be raised about 4", which was,
for me, a continual and intolerable annoyance.
At I keep looking for info but it seems hit and miss.[/color]
>
> Blocking Cross over is this a must and it also seems hit or miss some
> people say plugs come out and damage engine.
>
> I have seen 3 types Air Gap, RPM and Tork. but no one seems to say what
> they do.
>
> If you go to EFI is it better to have the Square mount and is that a
> reason to change intake?
>
>
>
> 1. Why change the manifold? (Weight is that only reason?)
> 2. Edelbrock 2151 why is this better or not better than stock
> 3. Rockwell seems expensive for the same thing as stock but lighter
> 4. Mondello (This on has no crossover)
> 5. Pro Comp Cheaper and looks like Mondello (crosswind)
> 6. Offenhauser Port O Sonic
>
> Does anyone know anything about these or have ratings on them performance
> over stock etc.
>
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
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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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