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Re: block off exhaust crossover on B manifold?
[Re: ademon]
#104254
08/13/08 03:12 PM
08/13/08 03:12 PM
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Joined: Jun 2005
Posts: 2,507
Royersford, PA
bschargerse
OP
master
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OP
master
Joined: Jun 2005
Posts: 2,507
Royersford, PA
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The car will be parked in the winter months, if the weather is mild I might take it out. The carb will have an electric choke. Unless I go with the AVS, in which case I'll have to leave the passage open for the choke coil.
Brian - 1971 Dodge Challenger
"The Dodge, which was practically stock, just left the Mustang like you wouldn't believe."
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Re: block off exhaust crossover on B manifold?
[Re: StealthWedge67]
#104258
08/14/08 03:09 PM
08/14/08 03:09 PM
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Joined: Jun 2005
Posts: 2,507
Royersford, PA
bschargerse
OP
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OP
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Joined: Jun 2005
Posts: 2,507
Royersford, PA
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I was thinking the same thing, isn't cooler air more dense, allowing for better atomization?
Brian - 1971 Dodge Challenger
"The Dodge, which was practically stock, just left the Mustang like you wouldn't believe."
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Re: block off exhaust crossover on B manifold?
[Re: bschargerse]
#104262
08/14/08 06:58 PM
08/14/08 06:58 PM
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Joined: Jun 2003
Posts: 21,503
It's a dry heat
gtx6970
Too Many Posts
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Too Many Posts
Joined: Jun 2003
Posts: 21,503
It's a dry heat
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Quote:
Is there a valley pan available with a blocked crossover
Yes.
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Re: block off exhaust crossover on B manifold?
[Re: bschargerse]
#104264
08/14/08 09:49 PM
08/14/08 09:49 PM
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Joined: Jul 2008
Posts: 30,490
Florida STAYcation
dOc …
The village idiot's idiot
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The village idiot's idiot
Joined: Jul 2008
Posts: 30,490
Florida STAYcation
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Quote:
I was thinking the same thing, isn't cooler air more dense, allowing for better atomization?
A warm/hot intake makes for better atomization.
Why do you think Ma Mopar puts heat in the intake ? ... and with a blocked crossover ... the mixture has to be fatter to make it more "driveable". That is the purpose of the choke ...correct?
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Re: block off exhaust crossover on B manifold?
[Re: 63stabamatic]
#104268
08/15/08 07:22 AM
08/15/08 07:22 AM
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Joined: Jan 2003
Posts: 75,094
A Banana Republic near you.
JohnRR
I Win
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I Win
Joined: Jan 2003
Posts: 75,094
A Banana Republic near you.
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Quote:
If you don't need the heat to operate the automatic choke then block it. I couldn't get my stock AVS choke to open all the way with the crossover blocked, even with a new choke control. I took the block out, now I wish I would have just changed carbs, as it's much hotter!
or just installed the electric choke off an ebrock on the AVS ....
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Re: block off exhaust crossover on B manifold?
[Re: dOc …]
#104269
08/15/08 07:25 AM
08/15/08 07:25 AM
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Joined: Jan 2003
Posts: 75,094
A Banana Republic near you.
JohnRR
I Win
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I Win
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Posts: 75,094
A Banana Republic near you.
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Quote:
You don't think that the A/F ratio goes rich on a cold-start ..... even when it is 70 degrees outside ?
it does to a degree by function of the choke flap being closed .
keep reaching
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Re: block off exhaust crossover on B manifold?
[Re: JohnRR]
#104270
08/15/08 07:34 AM
08/15/08 07:34 AM
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Joined: Jul 2008
Posts: 30,490
Florida STAYcation
dOc …
The village idiot's idiot
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The village idiot's idiot
Joined: Jul 2008
Posts: 30,490
Florida STAYcation
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 The "chat" here is IF the MPG will suffer. If the OP cares at-all about driveability and mpg ... he should NOT block the cross-over. Now the best POWER ? .. no doubt blocking the crossover will help. Keep REACHING ? ... You Double R have the "reach" of Mike Phelps !!  .....  ..... 
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Re: block off exhaust crossover on B manifold?
[Re: dOc …]
#104271
08/15/08 07:37 AM
08/15/08 07:37 AM
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Joined: Jan 2003
Posts: 75,094
A Banana Republic near you.
JohnRR
I Win
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I Win
Joined: Jan 2003
Posts: 75,094
A Banana Republic near you.
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Quote:
The "chat" here is IF the MPG will suffer. If the OP cares at-all about driveability and mpg ... he should NOT block the cross-over.
Now the best POWER ? .. no doubt blocking the crossover will help.
Keep REACHING ? ... You Double R have the "reach" of Mike Phelps !!
..... .....
The CHAT ... my god , not again ....
FACTS .... let's see them ...
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Re: block off exhaust crossover on B manifold?
[Re: stumpy]
#104274
08/15/08 12:27 PM
08/15/08 12:27 PM
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Joined: Jun 2005
Posts: 2,507
Royersford, PA
bschargerse
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OP
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Posts: 2,507
Royersford, PA
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well I would like it to get decent mileage, it gets around 18-20 mpg now. Driveability is great, the only problem I can't stand is the gas smell when I shut it off, it seems the gas is boiling out of the carb (original Stromberg 2bbl) and can be difficult to start when hot, and since I put dual exhaust on it, it seems to need more carb. I'm just trying to avoid the same thing with the 4bbl.
Brian - 1971 Dodge Challenger
"The Dodge, which was practically stock, just left the Mustang like you wouldn't believe."
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Re: block off exhaust crossover on B manifold?
[Re: stumpy]
#104276
08/15/08 05:16 PM
08/15/08 05:16 PM
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Joined: Jan 2003
Posts: 473
Fort Lauderdale, FL
Suregrip
mopar
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mopar
Joined: Jan 2003
Posts: 473
Fort Lauderdale, FL
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Just rebuild the car as it sounds like the needle and seat are not sealing the fuel into the bowl after engine shut-down. The residual fuel pressure after shut-down is pushing past the worn needle seat in the carb and dripping down into the engine. This is what you smell and also floods the engine when hot making it hard to start. I would rebuild the carb and leave the heat open to the carb...
Some people you just can't reach...
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Re: block off exhaust crossover on B manifold?
[Re: stumpy]
#104277
08/15/08 11:40 PM
08/15/08 11:40 PM
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Joined: Jul 2008
Posts: 30,490
Florida STAYcation
dOc …
The village idiot's idiot
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The village idiot's idiot
Joined: Jul 2008
Posts: 30,490
Florida STAYcation
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Quote:
Carb puts X amount of fuel into the intake and the intake temp doesn't change that. Thems the facts.
So you say the carb does not meter MORE fuel into the air-stream when the choke-blade is more closed-off than fully-open ? .... 
Wow .... your knowledge of the automotive fuel-system is OUTstanding ...NOT ! Why don't you go to the library and check-out a book - like Automotive 101.
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Re: block off exhaust crossover on B manifold?
[Re: JohnRR]
#104278
08/16/08 08:23 AM
08/16/08 08:23 AM
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Joined: Jan 2003
Posts: 1,796
Greer, SC
TooMany62s
top fuel
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top fuel
Joined: Jan 2003
Posts: 1,796
Greer, SC
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It depends. Every combination is different. I have a 440 in my truck with the crossover blocked and no choke. It starts and runs fine in warm weather or cold. The 383 in my '62 sedan is a different matter. With the crossover blocked and an electric choke it started just fine. But as soon as the choke pulls off, it wants to die at idle. Setting the choke richer didn't help. Electric chokes pull off pretty quickly. With the cross over blocked it needed to run about five minutes before it would idle well. If I set the idle up high enough to idle when cold, it was way to fast when it warmed up. I finally gave up, unblocked the crossover, it runs fine warm or cold. Keep in mind, engines aren't people, 70 degrees is cold.
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Re: block off exhaust crossover on B manifold?
[Re: dOc …]
#104279
08/16/08 11:01 AM
08/16/08 11:01 AM
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Joined: Jan 2003
Posts: 32,985
Grand Prairie,Texas
stumpy
I Win
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I Win
Joined: Jan 2003
Posts: 32,985
Grand Prairie,Texas
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Quote:
Quote:
Carb puts X amount of fuel into the intake and the intake temp doesn't change that. Thems the facts.
So you say the carb does not meter MORE fuel into the air-stream when the choke-blade is more closed-off than fully-open ? ....
Wow .... your knowledge of the automotive fuel-system is OUTstanding ...NOT ! Why don't you go to the library and check-out a book - like Automotive 101.
You didn't say anything about the choke and I took it that you weren't enetering that into the equation smart guy. We were talking about intake temp only.
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Re: block off exhaust crossover on B manifold?
[Re: badblack68]
#104284
08/18/08 09:26 AM
08/18/08 09:26 AM
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Joined: Jan 2003
Posts: 75,094
A Banana Republic near you.
JohnRR
I Win
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I Win
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Quote:
Intake temp controls the choke on the bi-metallic spring type chokes. Here`s another factor to consider, does your exhaust manifold heat riser valve work properly which also controls how fast the heat builds up in your intake? Does your exhaust manifold also have a heat stove with a flexible piece of ductwork to your aircleaner? These are all issues which will affect your fuel mileage at cold start and normal operating temperature.
please stop confusing the issue ...
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Re: block off exhaust crossover on B manifold?
[Re: dynorad]
#104287
08/18/08 04:23 PM
08/18/08 04:23 PM
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Joined: Aug 2004
Posts: 3,333
MARYLAND
69Cuda340S
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MARYLAND
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Quote:
Today's fuel evaporates much easier than fuel made in the 60's and 70's. That is why some people are able to get away with blocking the crossover and that is also why people have trouble with the fuel boiling inside the carb after shutoff. I have mine blocked and still have boiling issues. I am at high altitude and that makes it worse.
I put one of these on my car and was totally amazed and how much it reduced the fuel boiling:
http://store.summitracing.com/partdetail...mp;autoview=sku
Now I don't have to be embarrassed cranking my engine to get it started after I fill it up. I'll never run without one again.
I'll also add they will work on a Holley too.
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Re: block off exhaust crossover on B manifold?
[Re: dOc …]
#104289
08/18/08 10:40 PM
08/18/08 10:40 PM
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Joined: Jan 2003
Posts: 14,610
Not2farfromNashville, TN
Rug_Trucker
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 14,610
Not2farfromNashville, TN
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I have had no problem with an aluminum intake being blocked off on a small block. You have hot oil splashing on the bottom of the intake. That's what I did on my van. It has run in -2*
Aluminum heats up faster transfers heat faster.
Mom's '68 Polara 383 2bbl was a cold blooded beast! You had to be careful pulling into traffic with it cold. Same thing with my old 70 Bee with the iron intake.
I am surprised nobody mentioned cylinder wash down,fuel puddling etc........
"The only thing to do for triumph of evil is for good men to do nothing"
"NUNQUAM NON PARATUS!"
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