OEM intake manifolds and cracks, symptoms?

[gmc2000]

reading about the intake problems where the exhaust crossover heat becomes excessive, possibly when one side of the exhaust system has a leak. it
seems to be a very common problem (both the exhaust manifold leaks and cracked intakes)

but what are the symptoms of a cracked intake as it develops and progresses? I read Jim Bounds blog post about how the engine runs fine until it gets
up to operating temp then it wont take any throttle and just dies when you try to go above idle but is there any indications in drive-ability that it
may be cracking before the crack gets this big?

 

[johnny]

The simplest is to pick up the carb and have a look under there with a bright light.

--johnny
--
76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
"I forgive them all, save those who hurt the dogs. They must answer to me in hell" - ol Andy, paraphrased

 

[robert mueller]

G'day,

My take on the manifold crossover plenum follows.

The 455 was designed to go into a 4000 lb car when GMC installed it in a 10 - 12,000 lb motorhome the load as well as the heat it
produces went up BIGTIME!

The crossover plenum under the carb was there to heat up the carb when driving in Chicago winters.

I've noted that they crack in two locations:

1) the divider between the secondaries and the "floor" directly under it.

2) the "bottom" of the crossover plenum, quite often the crack is under the crack above.

JimB is correct in as much as while the engine is cold the crack doesn't open enough to effect engine performance noticeably. Once
at operating temperature you have engine vacuum sucking hot air from the crossover into the intake stream along with oil vapor from
the lifter valley.

The fix is easy, install a set of crossover block off plates from Dick Patterson:

http://www.springfield-ignition.com/gmc-motorhome/block-off-kits/

once you do that the crossover temps are:

http://www.gmcmhphotos.com/photos/aa-miscellaneous-photos/p63426-intake-manifold-internal-temp.html

If you're lucky the crack won't open up enough to effect performance.. You could possibly patch the crack with hi-temp epoxy of some
kind. If you blocked off the crossover ports with plates and evacuated the chamber you could suck the epoxy into the crack. I think
in that case I'd use hi temp (red) RTV.

Regards,
Rob M.
The Pedantic Mechanic
Sydney, Australia
AUS '75 Avion - The Blue Streak TZE365V100428
USA '75 Avion - Double Trouble TZE365V100426
USA '77 Kingsley - TZE 267V100808


-----Original Message-----
From: Gmclist [mailto:gmclist-bounces] On Behalf Of GMC2000
Sent: Monday, July 23, 2018 12:35 AM
To: gmclist
Subject: [GMCnet] OEM intake manifolds and cracks, symptoms?

reading about the intake problems where the exhaust crossover heat becomes excessive, possibly when one side of the exhaust system
has a leak. It seems to be a very common problem (both the exhaust manifold leaks and cracked intakes)

but what are the symptoms of a cracked intake as it develops and progresses? I read Jim Bounds blog post about how the engine runs
fine until it gets up to operating temp then it wont take any throttle and just dies when you try to go above idle but is there any
indications in drive-ability that it may be cracking before the crack gets this big?

 

[slc]

> reading about the intake problems where the exhaust crossover heat becomes excessive, possibly when one side of the exhaust system has a leak. it
> seems to be a very common problem (both the exhaust manifold leaks and cracked intakes)
>
> but what are the symptoms of a cracked intake as it develops and progresses? I read Jim Bounds blog post about how the engine runs fine until it
> gets up to operating temp then it wont take any throttle and just dies when you try to go above idle but is there any indications in drive-ability
> that it may be cracking before the crack gets this big?

I had a fuel system problem when we found by accident, the cracks in the exhaust crossover. So under this scenario, there were no symptoms. Also,
the cracks could not be seen. We removed the manifold for a different reason and the cracks didn't show up until we attempted to clean it. I had
cracks on both the top and bottom of the manifold and the crack lines did not show up until the cleaner was applied and wetted the metal. Even then,
these long cracks were difficult to see
When the fuel tanks were bypassed and I was using an aux tank, no symptoms and the engine would run fine. After looking at the cracks it was
determined that the cracks were not new at all, and had been there for a long time.
--
GatsbysCruise. \
74GMC260 Former Glacier Model style. \
Waukegan, Illinois \ Keep those MiniDiscs Spinning \ MY GREYHOUND IS FASTER THAN YOUR HONOR ROLL STUDENT \ WindowsXP-Win7-Win8.1-UBUNTU STUDIO -
UBUNTU VOYAGER - Berzin Auto Center

 

[Jim Hupy]

Cracked intake manifolds exhibit the exact symptoms you describe, as well
as higher than normal oil consumption. They run just fine when cold, but,
as the engine warms up, it runs worse and worse depending upon the severity
of the crack. If the floor of the inlet tract is cracked, it can easily be
seen by removing the carb and shining a powerful light source down the
intake.
If it is only cracked between the crossover and the engine valley, the
runability is not affected as much, but oil consumption will still be
prevalent.
Jim Hupy
Salem, Or

> > reading about the intake problems where the exhaust crossover heat
> becomes excessive, possibly when one side of the exhaust system has a leak.
> it
> > seems to be a very common problem (both the exhaust manifold leaks and
> cracked intakes)
> >
> > but what are the symptoms of a cracked intake as it develops and
> progresses? I read Jim Bounds blog post about how the engine runs fine
> until it
> > gets up to operating temp then it wont take any throttle and just dies
> when you try to go above idle but is there any indications in drive-ability
> > that it may be cracking before the crack gets this big?
>
>
>
> I had a fuel system problem when we found by accident, the cracks in the
> exhaust crossover. So under this scenario, there were no symptoms. Also,
> the cracks could not be seen. We removed the manifold for a different
> reason and the cracks didn't show up until we attempted to clean it. I had
> cracks on both the top and bottom of the manifold and the crack lines did
> not show up until the cleaner was applied and wetted the metal. Even then,
> these long cracks were difficult to see
> When the fuel tanks were bypassed and I was using an aux tank, no
> symptoms and the engine would run fine. After looking at the cracks it was
> determined that the cracks were not new at all, and had been there for a
> long time.
> --
> GatsbysCruise. \
> 74GMC260 Former Glacier Model style. \
> Waukegan, Illinois \ Keep those MiniDiscs Spinning \ MY GREYHOUND IS
> FASTER THAN YOUR HONOR ROLL STUDENT \ WindowsXP-Win7-Win8.1-UBUNTU STUDIO -
> UBUNTU VOYAGER - Berzin Auto Center
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

 

[gmc2000]

sellers wont want to remove the carb so a potential buyer can have a look though. and Im also trying to get an idea of what is happening to make them
run bad (backfires or just lack of power or something other?) and stall out.

when the crack is that bad, is it pulling crankcase oil vapors in and then fouling out the spark? or is it pulling exhaust gases in or a little of
both?

Ive seen some of the pics posted of the manifolds that were cracked but its still hard to tell what is actually happening and since Mondello and
others have been filling the crossovers with various alloys and composites, I guess that if the manifold is cracked then its too late for block off
plates then, right?

when they are running bad from this, I suspect most would think a fuel problem at first. if there is excessive oil consumption, that should show up on
the spark plugs I guess but I doubt a seller would want to let someone pull them out or let them also do a compression test (hot) either. I dunno..

I havnt asked (I think it would be too much to ask unless the price was high and firm) but I do ask that it be stone cold when I arrive to look at it
and will now ask for an extended test drive too.

there really is a whole lot to evaluate on these. ideally, I'd want to spend a few hours going over one instead of just rolling the dice. lol but
there is always something even when you think you have everything covered.

If Explorer ever makes a GMCIII, I would get that line!

 

[jerry burt]

I don't know if you have found this list or someone has pointed you to it. I suggest you take a look and print it out.
I had it when looking for my coach relied my "mechanical expertise" and didn't follow through on the list.
http://www.bdub.net/publications/gmcsearch/buyer.htm
--
Patti & Jerry Burt
73 Gmc 26' Canyon Lands -
77 Palm Beach
Members: FMCA - GMCMI - GMCWS

 

[gmc2000]

> I don't know if you have found this list or someone has pointed you to it. I suggest you take a look and print it out.
> I had it when looking for my coach relied my "mechanical expertise" and didn't follow through on the list.
> http://www.bdub.net/publications/gmcsearch/buyer.htm

thanks, I posted that one in the sanbox thread "Advice on buying my first GMC coach?" its better than nothing but not real specific.

be great to have a more comprehensive one written by someone like Jim Bounds or something. but yeah, one could easily spend a whole day going over
everything and then if they decide not to buy for whatever reason its a pretty big waste of time for both parties.

reading Jim B's blog, he wrote that pretty much all the manifolds are cracked and its very rare for one not to have a crack. I guess just figure that
into the plan unless its got a documented repair or that high dollar, aftermarket, aluminum one. or just be ready to do that when the crack spreads
enough to be a problem.

I guess if the crack is not big enough to be, the block off plates would help keep it from spreading to that point?

 

[johnny]

'sellers wont want to remove the carb so a potential buyer can have a look though. and Im also trying to get an idea of what is happening to make them
run bad (backfires or just lack of power or something other?) and stall out.'

"I'll offer you $XXX contingent on inspection of the intake manifold below the carburetor." No lookee, no interest.

--johnny

DOS Tip - have the seller take pictures while you're looking to save taking the carb off again.

--
76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
"I forgive them all, save those who hurt the dogs. They must answer to me in hell" - ol Andy, paraphrased

 

[jim kanomata1]

You need to be realistic and forget taking a carb off.
There are indicators by loving at both sides left and right of carb for
white heat signs.

On Wed, Jul 25, 2018 at 6:44 AM Johnny Bridges via Gmclist <

> 'sellers wont want to remove the carb so a potential buyer can have a look
> though. and Im also trying to get an idea of what is happening to make them
> run bad (backfires or just lack of power or something other?) and stall
> out.'
>
> "I'll offer you $XXX contingent on inspection of the intake manifold below
> the carburetor." No lookee, no interest.
>
> --johnny
>
> DOS Tip - have the seller take pictures while you're looking to save
> taking the carb off again.
>
> --
> 76 26' Eleganza(?) with beaucoup mods and add - ons.
> Braselton, Ga.
> "I forgive them all, save those who hurt the dogs. They must answer to me
> in hell" - ol Andy, paraphrased
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
--
Jim Kanomata
Applied/GMC, Newark,CA
jimk
http://www.appliedgmc.com
1-800-752-7502

 

[sgltrac]

Got it. Love both sides and hope you don’t leave white heat signs.
Check.

Sully
Bellevue wa.

> You need to be realistic and forget taking a carb off.
> There are indicators by loving at both sides left and right of carb for
> white heat signs.
>
> On Wed, Jul 25, 2018 at 6:44 AM Johnny Bridges via Gmclist <

>
> > 'sellers wont want to remove the carb so a potential buyer can have a
> look
> > though. and Im also trying to get an idea of what is happening to make
> them
> > run bad (backfires or just lack of power or something other?) and stall
> > out.'
> >
> > "I'll offer you $XXX contingent on inspection of the intake manifold
> below
> > the carburetor." No lookee, no interest.
> >
> > --johnny
> >
> > DOS Tip - have the seller take pictures while you're looking to save
> > taking the carb off again.
> >
> > --
> > 76 26' Eleganza(?) with beaucoup mods and add - ons.
> > Braselton, Ga.
> > "I forgive them all, save those who hurt the dogs. They must answer to
> me
> > in hell" - ol Andy, paraphrased
> >
> >
> > _______________________________________________
> > GMCnet mailing list
> > Unsubscribe or Change List Options:
> > http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
> >
> --
> Jim Kanomata
> Applied/GMC, Newark,CA
> jimk
> http://www.appliedgmc.com
> 1-800-752-7502
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

 

[jim kanomata1]

Sully,
I have been on both sides of the fence, and if I asked a dealer if I can
remove the carb, they will brand me as another A Hole Asian.
I know I am, but do not need to have me reminded.
The White particales on the runner on the intake is a very positive
indicator that the intake can be cracked, or will be..
A set of Good Truck duty mufflers need to be used, not the standard car.
One side goes bad, the exaust takes the route through the intake and heats
it up good and Red, leaving a white oxide coating.

> Got it. Love both sides and hope you don’t leave white heat signs.
> Check.
>
> Sully
> Bellevue wa.
>
> On Wed, Jul 25, 2018 at 6:50 AM Jim Kanomata

>
> > You need to be realistic and forget taking a carb off.
> > There are indicators by loving at both sides left and right of carb for
> > white heat signs.
> >
> > On Wed, Jul 25, 2018 at 6:44 AM Johnny Bridges via Gmclist <

> >
> > > 'sellers wont want to remove the carb so a potential buyer can have a
> > look
> > > though. and Im also trying to get an idea of what is happening to make
> > them
> > > run bad (backfires or just lack of power or something other?) and stall
> > > out.'
> > >
> > > "I'll offer you $XXX contingent on inspection of the intake manifold
> > below
> > > the carburetor." No lookee, no interest.
> > >
> > > --johnny
> > >
> > > DOS Tip - have the seller take pictures while you're looking to save
> > > taking the carb off again.
> > >
> > > --
> > > 76 26' Eleganza(?) with beaucoup mods and add - ons.
> > > Braselton, Ga.
> > > "I forgive them all, save those who hurt the dogs. They must answer to
> > me
> > > in hell" - ol Andy, paraphrased
> > >
> > >
> > > _______________________________________________
> > > GMCnet mailing list
> > > Unsubscribe or Change List Options:
> > > http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
> > >
> > --
> > Jim Kanomata
> > Applied/GMC, Newark,CA
> > jimk
> > http://www.appliedgmc.com
> > 1-800-752-7502
> > _______________________________________________
> > GMCnet mailing list
> > Unsubscribe or Change List Options:
> > http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
> >
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

--
Jim Kanomata
Applied/GMC, Newark,CA
jimk
http://www.appliedgmc.com
1-800-752-7502

 

[sgltrac]

Jim,

I do not dispute or mock your intellect or knowledge. Only poking a little
fun at your typo

Sully
Bellevue wa.

> Sully,
> I have been on both sides of the fence, and if I asked a dealer if I can
> remove the carb, they will brand me as another A Hole Asian.
> I know I am, but do not need to have me reminded.
> The White particales on the runner on the intake is a very positive
> indicator that the intake can be cracked, or will be..
> A set of Good Truck duty mufflers need to be used, not the standard car.
> One side goes bad, the exaust takes the route through the intake and heats
> it up good and Red, leaving a white oxide coating.
>

>
> > Got it. Love both sides and hope you don’t leave white heat signs.
> > Check.
> >
> > Sully
> > Bellevue wa.
> >
> > On Wed, Jul 25, 2018 at 6:50 AM Jim Kanomata

> >
> > > You need to be realistic and forget taking a carb off.
> > > There are indicators by loving at both sides left and right of carb for
> > > white heat signs.
> > >
> > > On Wed, Jul 25, 2018 at 6:44 AM Johnny Bridges via Gmclist <

> > >
> > > > 'sellers wont want to remove the carb so a potential buyer can have a
> > > look
> > > > though. and Im also trying to get an idea of what is happening to
> make
> > > them
> > > > run bad (backfires or just lack of power or something other?) and
> stall
> > > > out.'
> > > >
> > > > "I'll offer you $XXX contingent on inspection of the intake manifold
> > > below
> > > > the carburetor." No lookee, no interest.
> > > >
> > > > --johnny
> > > >
> > > > DOS Tip - have the seller take pictures while you're looking to save
> > > > taking the carb off again.
> > > >
> > > > --
> > > > 76 26' Eleganza(?) with beaucoup mods and add - ons.
> > > > Braselton, Ga.
> > > > "I forgive them all, save those who hurt the dogs. They must answer
> to
> > > me
> > > > in hell" - ol Andy, paraphrased
> > > >
> > > >
> > > > _______________________________________________
> > > > GMCnet mailing list
> > > > Unsubscribe or Change List Options:
> > > > http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
> > > >
> > > --
> > > Jim Kanomata
> > > Applied/GMC, Newark,CA
> > > jimk
> > > http://www.appliedgmc.com
> > > 1-800-752-7502
> > > _______________________________________________
> > > GMCnet mailing list
> > > Unsubscribe or Change List Options:
> > > http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
> > >
> > _______________________________________________
> > GMCnet mailing list
> > Unsubscribe or Change List Options:
> > http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
> >
>
>
>
> --
> Jim Kanomata
> Applied/GMC, Newark,CA
> jimk
> http://www.appliedgmc.com
> 1-800-752-7502
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

 

[jim kanomata1]

Sully,
My finger hae been in places that it did not belong, so it does strange
things, Ha Ha.

> Jim,
>
> I do not dispute or mock your intellect or knowledge. Only poking a little
> fun at your typo
>
> Sully
> Bellevue wa.
>
> On Wed, Jul 25, 2018 at 11:36 AM Jim Kanomata

>
> > Sully,
> > I have been on both sides of the fence, and if I asked a dealer if I can
> > remove the carb, they will brand me as another A Hole Asian.
> > I know I am, but do not need to have me reminded.
> > The White particales on the runner on the intake is a very positive
> > indicator that the intake can be cracked, or will be..
> > A set of Good Truck duty mufflers need to be used, not the standard car.
> > One side goes bad, the exaust takes the route through the intake and
> heats
> > it up good and Red, leaving a white oxide coating.
> >
> > On Wed, Jul 25, 2018 at 10:54 AM, Todd Sullivan

> >
> > > Got it. Love both sides and hope you don’t leave white heat signs.
> > > Check.
> > >
> > > Sully
> > > Bellevue wa.
> > >
> > > On Wed, Jul 25, 2018 at 6:50 AM Jim Kanomata

> > >
> > > > You need to be realistic and forget taking a carb off.
> > > > There are indicators by loving at both sides left and right of carb
> for
> > > > white heat signs.
> > > >
> > > > On Wed, Jul 25, 2018 at 6:44 AM Johnny Bridges via Gmclist <

> > > >
> > > > > 'sellers wont want to remove the carb so a potential buyer can
> have a
> > > > look
> > > > > though. and Im also trying to get an idea of what is happening to
> > make
> > > > them
> > > > > run bad (backfires or just lack of power or something other?) and
> > stall
> > > > > out.'
> > > > >
> > > > > "I'll offer you $XXX contingent on inspection of the intake
> manifold
> > > > below
> > > > > the carburetor." No lookee, no interest.
> > > > >
> > > > > --johnny
> > > > >
> > > > > DOS Tip - have the seller take pictures while you're looking to
> save
> > > > > taking the carb off again.
> > > > >
> > > > > --
> > > > > 76 26' Eleganza(?) with beaucoup mods and add - ons.
> > > > > Braselton, Ga.
> > > > > "I forgive them all, save those who hurt the dogs. They must
> answer
> > to
> > > > me
> > > > > in hell" - ol Andy, paraphrased
> > > > >
> > > > >
> > > > > _______________________________________________
> > > > > GMCnet mailing list
> > > > > Unsubscribe or Change List Options:
> > > > > http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
> > > > >
> > > > --
> > > > Jim Kanomata
> > > > Applied/GMC, Newark,CA
> > > > jimk
> > > > http://www.appliedgmc.com
> > > > 1-800-752-7502
> > > > _______________________________________________
> > > > GMCnet mailing list
> > > > Unsubscribe or Change List Options:
> > > > http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
> > > >
> > > _______________________________________________
> > > GMCnet mailing list
> > > Unsubscribe or Change List Options:
> > > http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
> > >
> >
> >
> >
> > --
> > Jim Kanomata
> > Applied/GMC, Newark,CA
> > jimk
> > http://www.appliedgmc.com
> > 1-800-752-7502
> > _______________________________________________
> > GMCnet mailing list
> > Unsubscribe or Change List Options:
> > http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
> >
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

--
Jim Kanomata
Applied/GMC, Newark,CA
jimk
http://www.appliedgmc.com
1-800-752-7502

 

[john r. lebetski]

Jim you should blame auto-correct. "I know one time I thought I was wrong, but I was mistaken".
--
John Lebetski
Woodstock, IL
77 Eleganza II

 

[jim kanomata1]

No Sh-t, not going to get better.

On Thu, Jul 26, 2018 at 7:26 AM, John R. Lebetski
wrote:

> Jim you should blame auto-correct. "I know one time I thought I was wrong,
> but I was mistaken".
> --
> John Lebetski
> Woodstock, IL
> 77 Eleganza II
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

--
Jim Kanomata
Applied/GMC, Newark,CA
jimk
http://www.appliedgmc.com
1-800-752-7502

 

[LarryW]

Don't know if anyone has mentioned this yet, but here goes.

Take your manifold to your nearest foundry. Put a block-off plate on one or the other crossover ports and have them pour it full of aluminum. See
this:

http://www.gmcmhphotos.com/photos/g4571-pouring-the-455-crossover.html

It did two things. Blocked the crossover, and even though the manifold did not cracks, it would seal manifold cracks. Think I paid $25 or so. Still
put the SS plates on the ports to keep exhaust gasses from reaching the aluminum. Didn't think it would be a problem, but did it anyway as a safety
measure. JWID
--
Larry
78 Royale w/500 Caddy
Menomonie, WI.

 

[Jim Hupy]

Don't know if that aluminum pour is necessary, but it should work,
particularly if the block off plates are used. It can't hurt anything. Some
people, the money to pour the aluminum is no big deal, yet, some would
resist that expenditure like having their wisdom teeth pulled. Each his
own, I say.
Jim Hupy
Salem, OREGON
78 GMC ROYALE 403

> Don't know if anyone has mentioned this yet, but here goes.
>
> Take your manifold to your nearest foundry. Put a block-off plate on one
> or the other crossover ports and have them pour it full of aluminum. See
> this:
>
> http://www.gmcmhphotos.com/photos/g4571-pouring-the-455-crossover.html
>
> It did two things. Blocked the crossover, and even though the manifold did
> not cracks, it would seal manifold cracks. Think I paid $25 or so. Still
> put the SS plates on the ports to keep exhaust gasses from reaching the
> aluminum. Didn't think it would be a problem, but did it anyway as a safety
> measure. JWID
> --
> Larry
> 78 Royale w/500 Caddy
> Menomonie, WI.
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

 

[Ken H.]

Or, for those who insist on DIY:
http://www.gmcmhphotos.com/photos/g3115-plugging-intake-manifold-exhaust-crossover.html

Ken H.

> Don't know if anyone has mentioned this yet, but here goes.
>
> Take your manifold to your nearest foundry. Put a block-off plate on one
> or the other crossover ports and have them pour it full of aluminum. See
> this:
>
> http://www.gmcmhphotos.com/photos/g4571-pouring-the-455-crossover.html
>
> It did two things. Blocked the crossover, and even though the manifold did
> not cracks, it would seal manifold cracks. Think I paid $25 or so. Still
> put the SS plates on the ports to keep exhaust gasses from reaching the
> aluminum. Didn't think it would be a problem, but did it anyway as a safety
> measure. JWID
> --
> Larry
> 78 Royale w/500 Caddy
> Menomonie, WI.
>
>

 

[Rdenney]

What I’m laughing about is the notion of a “local” foundry. The only
“industries” around here that use a flame are the micro-breweries that
serve barbecue.

(I use a Rockwell manifold with stainless block-off plates.)

Rick “nothing gets produced around here except paper and hot air” Denney

On Thu, Jul 26, 2018 at 7:08 PM Ken Henderson
wrote:

> Or, for those who insist on DIY:
>
> http://www.gmcmhphotos.com/photos/g3115-plugging-intake-manifold-exhaust-crossover.html
>
> Ken H.
>
> --
Rick Denney
73 x-Glacier 230 "Jaws"
Off-list email to rick at rickdenney dot com