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Discussion Starter #1
How is this done and what is it? I have a 1991 L98... I have heard bout this but never really knew what they mean't by it. Anyone
 

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Port and polish is a process to relieve any restrictions and smooth the air flow thru the intake and exhaust ports in cylinder heads.

It is usually done with a high speed grinder and polisher.
 

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Either can be done with the right equipment. If you have a smooth hand and a dremel tool you just have to take the sandpaper feel off of the surface that air touches. Make it nice and smooth and even.
 

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Discussion Starter #5
By any Crazy chance do you have a how to or any pictures on how its done?
 

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By crazy chance I do. :laughing:

These are photos of the plenum, runners and intake manifold. Not the best but I think you'll see enough to get the idea of what I did. Tools used were a Dremel and air powered die grinder. I used the die grinder for most of the job. The first step I took was cut out the center portion of the plenum/runner/manifold gaskets, siameseing them. There is an embossed portion on those gaskets. I trimmed the access paper that was to the inside of the embossed part, in essence making the hole larger. I then traced the outline of the gasket on the plenum, runners and intake manifold. Below I am pointing to the embossed part of the gasket.



You can see in this photo some of the black marker on the plenum. This is the shape the gasket took when I cut it down. I cut the part until all the marker was gone. Of course I wasn't done yet when I took the photo. ;)



Another image of the plenum shows the "after" version when I chopped off the 2 ledges that were inside the TB opening. I also opened up the bores just a little and cleaned up some of the sides. You can see where I ported by the shiny look. If you look deeper into the plenum you can see where it's darker, not touched.



The runners were a different animal. You can only cut so deep. If you go too deep you'll break through the flange.



I think the "1/4" in this next photo means I only went 1/4 in. deep on those cuts.



So far you can see in those, and the following photos, that I didn't get very far in polishing the inside of the runners. I tore up a lot of tapered cartrige rolls trying to get as deep as possible. I probably could have found something to get all the way through but at this point in time I was w/o my Vette for a few months and it was time to get it put back together. The Vette was in the shop for a head gasket replacement that turned into a cam swap, gear change...etc. ;) :laughing:



In these photos, hopefully you can see the cut I made between the runners in the intake manifold. I siamesed those and cut it down about an inch or so. I used to have all the measurements but not anymore.




The part of the intake manifold that mates to the head I touched up. I don't recall messing around in that area too much.

Now I will say this, I did not dyno or get track times after doing this job. Even if I did, it would be hard to tell if I had any gains from it due to the amount of "other" work that was done at the time. I can firmly say that it did allow the motor to "pull" at a higher rpm. I was still feeling it pull into the 5k rpm range. I don't know that it would matter much w/ the stock cam. I had installed the hotcam before I got this put back on the motor.

Hope this helped,

John
 

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Discussion Starter #7
Hey War Machine and other that have tried this.... do you feel or does it really make a difference if you do it to the Plenium and the Runners? I am kinda scraed oftrying this and messing something up....
 

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Frankylo can you explain the picture in your avatar, please. It looks like the car left the trailer and hit the truck. Is that your car?
 

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Yup Thats my new baby. Unfortunat that the previous owner didnt tell me That the park does not work. Good things is that is was a hair away from hitting my truck And nothing happened to the vette Either. plus thats The only picture i got right now.
 

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Hey War Machine and other that have tried this.... do you feel or does it really make a difference if you do it to the Plenium and the Runners? I am kinda scraed oftrying this and messing something up....
You could clean up the front of the plenum where the TB attaches and not touch the runners. It wouldn't make sense to port and siamese the plenum w/o doing the runners. You could also port/siamese the plenum and the side of the runners that connect to the plenum and not do the intake base. I did a search on this and grumpyvette said siamesing the base will cost you torque. Here's the link, it's a good read.

Porting a TPI
 

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Great find John. I had almost forgot about Grumpy's post about that. :thumbsup:
 

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Discussion Starter #13
Hey wasn't there some more if I think that Grumpy Vette had Posted? It just dissappeared... Can I see it one more time
 

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Discussion Starter #14
By anychance can the Intake on the LT1 be ported and polished too? Or can anything be done to it and is there a how to just like the TPI.
 
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