Re: Porting HP 440 exhaust manifolds?
[Re: Stewpar]
#1316176
10/09/12 12:06 AM
10/09/12 12:06 AM
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Joined: Oct 2010
Posts: 295 Greensburg, Pa
Mpetros
enthusiast
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enthusiast
Joined: Oct 2010
Posts: 295
Greensburg, Pa
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Quote:
Here's another option......
http://www.extrudehone.com/auto/auto-performance.php
I ran in a Class that You had to have Stock Manifolds.
I gasket matched a set and then sent the to get Power Flow.. The Extrudehone makes the like a glass finish the whole way thru.. You could never get in there to polish them like the Power Flow does..
If You call them ask for Joe in Power Flow.. He knows whats going on.
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Re: Porting HP 440 exhaust manifolds?
[Re: BSB67]
#1316178
10/09/12 07:05 PM
10/09/12 07:05 PM
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Joined: Feb 2005
Posts: 4,333 Prospect, PA
BSB67
master
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master
Joined: Feb 2005
Posts: 4,333
Prospect, PA
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Quote:
What is the ID of your exhaust tubing?
Have you measured the inside diameter of the exhaust pipe yet? I think it is 2 3/8". Mine are.
If it is, you really dont want to step down from 2 1/2 to 2 3/8 in the direction of flow.
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Re: Porting HP 440 exhaust manifolds?
[Re: BSB67]
#1316179
10/09/12 10:43 PM
10/09/12 10:43 PM
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Joined: Jan 2003
Posts: 1,586 Tampa, FL
tpabayflyer
OP
pro stock
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OP
pro stock
Joined: Jan 2003
Posts: 1,586
Tampa, FL
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Good question... I did not consider that but I think you are right! Thinking about using the TTI down pipes in the 3" size and then 2 1/2 after the x-pipe to the tailpipes... If I have to grind out the head pipes to 2 1/2 than I guess I will have too..... I will get with TTI tomorrow and ask them the inside diameter of there headpipes.... I already opened up the exhaust flanges to the 2 1/2" size so I may have to fire up the ole makita die grinder and let it rip on the headpipes when I get them! TBF
71 Challenger 528 Hemi project 09 Gr Cherokee 5.7 hemi in da house!!
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Re: Porting HP 440 exhaust manifolds?
[Re: tpabayflyer]
#1316181
10/25/12 12:09 PM
10/25/12 12:09 PM
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Joined: Jan 2003
Posts: 1,586 Tampa, FL
tpabayflyer
OP
pro stock
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OP
pro stock
Joined: Jan 2003
Posts: 1,586
Tampa, FL
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After a bit of research it looks like the max gain to expect from porting the HP exhaust is a few peak horsepower gain...... However, there was a gain of 10ft/lbs of torque in the mid rpm range so every little bit helps! TBF
71 Challenger 528 Hemi project 09 Gr Cherokee 5.7 hemi in da house!!
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Re: Porting HP 440 exhaust manifolds?
[Re: lenny459]
#1316183
11/19/12 11:17 AM
11/19/12 11:17 AM
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Joined: Oct 2012
Posts: 1,106 Northeast
VincentVega
super stock
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super stock
Joined: Oct 2012
Posts: 1,106
Northeast
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Here is my opinion. You are doing yourself a disservice HP-wise by sticking with manifolds. I understand the argument for manifolds on the street. They're cheap, reliable, and you already own them. That, and headers are known for being a PITA. Then there's the installation, the scraping, the leaking... blah What is the argument FOR headers? properly sized, better HP and toque all across the range. In your scope, for something around 500HP, you're almost assuredly giving up 40-60hp (this is dyno proven) by not using a good header and appropriately sized exhaust. So the question becomes: do you care? if not, stick with what you got, and you'll never have to worry about exhaust until rust eats a hole in it somewhere. If you want the reliability, don't hog out the outlets for reasons stated. You won't feel the gain, but the cast iron will feel the loss. By all means gasket match if you feel there is enough meat there, and take off the sharp edges. beyond that, I'd live with them as-is. or find some of those nice max-wedge cast iron headers
Looking for 1975 through 1978 B body 4 door sedan sheet metal or parts cars - monaco, fury, coronet. Please let me know
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Re: Porting HP 440 exhaust manifolds?
[Re: VincentVega]
#1316184
11/19/12 08:12 PM
11/19/12 08:12 PM
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Joined: Jan 2003
Posts: 4,046 Minnesota
72blubird
master
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master
Joined: Jan 2003
Posts: 4,046
Minnesota
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You will lose power. I did comparison on a dyno in August. 502hp with headers at 5800 rpm and climbing to 468 hp at 5400 rpm. About a 7% loss is that enough to deal with headers that you can only decide. This motor is stroker 400 w/ aluminum heads and intake exhaust not matched.
What was I thinking....
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