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Discussion Starter #1 (Edited)
For the peole wanting headers but not having 700 for kooks headers or taking a chance on jba headers here is a cheap and almost free performance improvement. I ported a set of production 4.6 cast iron manifolds. It should help make more power from improved airflow. I have not done any seintific testing to prove this but it should be true. On the factory 4.6 manifolds they have about a 1/8 inch lip inside the manifold reducing flow. I cut this out and enlarged the outlet opening to improve airflow. The driverside is difficult to improve flow because where the factory indented it so that it was easier to install the manifolds from the factory. I had to cut more out of one side than the other. If you look close at the inside of the driverside you can see a little bit of the ring still in there. It is much shorter than before.







 

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Damn man, re-size the pics, WAY 2 big..
 

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Are the '95 manifolds the same as '96-'97? I'm thinking of getting an extra set from the junk yard and getting them ported (perhaps port-matched to '96 heads). I just hope they're not a different size or fit on the '95 block.
 

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guitar maestro said:
are those going on your SC'd bird or are you sellin 'em? :)
He's running Kooks header so he has no need for something that is now in my garage.... ;) :thumbsup:
 

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Discussion Starter #6
The manifolds are the same form 94-97 on the birds. I ported the manifolds and gave them to allen to help his allen breath better and since 700.00 for kooks is a little hard to swollow at this time. If I have a bird and I wanted more flow and could not afford the kooks I would do this insted of puting JBA crack headers.

If you look at the passanger side you will notice I just took the 3/16 tall ring out of the inside. but did not cut back the collector a tremendous amount. I also removed casting slag from the inside of the manifold and opend it up on the exhaust port to match the edege of the gasket.

I did the same port matching on the driverside. The driverside requires a lot more work that then passanger side. The problem with the driverside is the indention from the factory to facilite instalation . It reduces flow. I cut the ring back but you can't cut back a lot on the indention side. I did however cut back on the side oppsite of the indention a lot more. I ran out of time or I would have cut it back to the edge of the gasket. The flow should be up though because of the restriction being snifigantly reduced.
 

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just bought some spare headers for $15, I am going to try and do the same. Thanks alot!
 

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i have 2 spare sets ill do that also, btw nice tire choice i had them in 245/50 size on the back of my bird before it got 18s
 

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would these be semi comparable to jba headers?
 

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So do any of you have pictures of ported/polished cylinder heads? I just want to make sure mine look comparable to what the pros are doing.(hand porting and polishing is a LOT of work!)
 

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Sorry to bring this old thread up but blown96, how did you know how much to take out of the passenger side collector so it wouldnt be too much. I am currently porting a set.

Thanks
Will
 

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Discussion Starter #13
I took out the raised inner ring and made it leval with the rest of the inner diameter. I was just trying to make it even. I should have worked the driveside over more. I took out the ring on the dirverside but should have cut more out oppsite of the buldge to help make up some of the area that the buldge comsumes.
 

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