Head Porting Questions
Thread Starter
Racer
Joined: Sep 2004
Posts: 400
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From: Phoenix AZ
Head Porting Questions
What exactly does each stage represent when I read about stage I , II, III porting? And are all stages the same regardless of who ported them. For example would Stage II heads from Exotic Muscle be the same as Stage II heads from AFR ?
Le Mans Master
Joined: Jul 1999
Posts: 8,683
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From: Phoenix AZ
Originally Posted by 94brick
What exactly does each stage represent when I read about stage I , II, III porting? And are all stages the same regardless of who ported them. For example would Stage II heads from Exotic Muscle be the same as Stage II heads from AFR ?
Large Impressive Member
Joined: Jul 2003
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From: Good health is merely the slowest possible rate at which one can die
St. Jude Donor '04-'05-'06-'07
Usually, stage I is port matching and a little massaging, stage II is serious porting and stage III adds larger valves and other niceties. Here's a website with all the info you need plus a great company to do business with.
http://www.precisionporting.com/highlights.html
http://www.precisionporting.com/highlights.html
Large Impressive Member
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From: Good health is merely the slowest possible rate at which one can die
St. Jude Donor '04-'05-'06-'07
And here are the flow numbers on my Stage III heads from them:
LIFT INT EXH
0.1000 85.3 67.2
0.2000 143.7 117.5
0.3000 204.4 174.6
0.4000 247.9 199.0
0.5000 273.9 224.6
0.6000 281.8 230.9
0.6500 282.0 231.4
LIFT INT EXH
0.1000 85.3 67.2
0.2000 143.7 117.5
0.3000 204.4 174.6
0.4000 247.9 199.0
0.5000 273.9 224.6
0.6000 281.8 230.9
0.6500 282.0 231.4
Race Director
Joined: Jan 2002
Posts: 12,263
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From: O'Fallon Missouri
Exhaust Flow
Corvette Kid, those are some really strong exhaust flow numbers for an LT1. Did you have your heads independently flow tested, or are they the porters advertised numbers?
Large Impressive Member
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From: Good health is merely the slowest possible rate at which one can die
St. Jude Donor '04-'05-'06-'07
Originally Posted by STL94LT1
Corvette Kid, those are some really strong exhaust flow numbers for an LT1. Did you have your heads independently flow tested, or are they the porters advertised numbers?
Last edited by Corvette Kid; Dec 26, 2004 at 09:59 AM.
Race Director
Joined: Jan 2002
Posts: 12,263
Likes: 86
From: O'Fallon Missouri
CKNC,Those flow numbers are stronger than the AFR 195cc competition ported LT4 heads. You should be putting out some strong hp/tq #'s. 
I remember your dyno #'s being pretty weak. Did you get your tuning/exhaust problems worked out?
I remember your dyno #'s being pretty weak. Did you get your tuning/exhaust problems worked out?
Last edited by STL94LT1; Dec 26, 2004 at 09:58 AM.
Large Impressive Member
Joined: Jul 2003
Posts: 65,811
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From: Good health is merely the slowest possible rate at which one can die
St. Jude Donor '04-'05-'06-'07
Originally Posted by STL94LT1
CKNC,Those flow numbers are stronger than the AFR 195cc competition ported LT4 heads. You should be putting out some strong hp/tq #'s.
I remember your dyno #'s being pretty weak. Did you get your tuning/exhaust problems worked out?
I remember your dyno #'s being pretty weak. Did you get your tuning/exhaust problems worked out?
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Large Impressive Member
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From: Good health is merely the slowest possible rate at which one can die
St. Jude Donor '04-'05-'06-'07
Originally Posted by jimbomill
Chris, Do those HP numbers translate to about 420-425 at the crank then, assuming about 20% loss? Is that about what you expected?
