Gasket matching Upper intake runners

[grandprix34]

I now have my air compressor and die grinder up and running so I'm itching for a project. What I wanted to do is pull the plenum and gasket match the runners.

Several questions I had regarding this:
1. How can I scribe onto the intake runners so I don't have to leave the gasket on the runners?
2. Has anyone done this before?
3. About how deep does the runner go and would their be any benefits in going in deeper thant the port itself?
4. Would there be noticeable gains in doing this?

[montessgtp]

I have a ported lower done by ben n i gasket matched up my upper..but the problem with the upper is u cant get in real deep... i basically could only get in bout 2 inches or so..with a long shank. I however noticed a slight diffrence with the porter lower...im assuming this would work best with a bigger throttle body or head port work. ....good luck...

[LQ1]

i went in about 2inches on my plenum, noticed a little nothing to brag about. I used a permanent marker to mark the areas that needed work.

[Anonymous]

Doing the 2in on the upper plenum didn't help me any, since the biggest restriction is where the air is turned around at the very back of the plenum.

Gasket matching a gasket to stock manis won't do any good, it will just cause leaks.

[montessgtp]

How do u figure it will cause leaks? I did mine...i didnt have anything leak... Gasket matching your grinding 2mm at most around the intake walls... blah w/e

[Anonymous]

Stock the gaskets will match perfectly, so you are just grinding away gasket that doesn't need to be, and out of the 5mm gasket thickness you grind 2, well than you just have 3 sealing it.

But hey, the 58hp you gained is all wroth it right....

[4spdz34]

Stock the gaskets will match perfectly, so you are just grinding away gasket that doesn't need to be, and out of the 5mm gasket thickness you grind 2, well than you just have 3 sealing it.

But hey, the 58hp you gained is all wroth it right....

what the hell are u smoking? obviously u ahve never ported before or even looked at the gasket opening compared to the plenum or lim. u can take material out just so u match the gasket. u don't cut the gasket at all.

[LQ1]

wow, and i thought you knew atleast something about cars since you built and installed headers aaron. i guess i was wrong.

[jmgtp]

Stock the gaskets will match perfectly, so you are just grinding away gasket that doesn't need to be, and out of the 5mm gasket thickness you grind 2, well than you just have 3 sealing it.

But hey, the 58hp you gained is all wroth it right....

what the hell are u smoking? obviously u ahve never ported before or even looked at the gasket opening compared to the plenum or lim. u can take material out just so u match the gasket. u don't cut the gasket at all.

I'll side with Aaron on this one. On my 91 manifolds the plenum gasket matched the lower intake perfectly and matched the plenum perfectly. So I would call that a perfect match from the factory. My 96 manifolds the same results. You have to keep in mind that these are cast manifolds so some may match better than others. If the gasket is bigger than the ports then there really isnt a point in matching them, since the gasket won't be disturbing flow. Porting it bigger to meet the gasket would be utterly pointless unless you did the entire length of the runners.

[Anonymous]

Out of the 3 gaskets I've put in the car, for random reasons, every gasket matched perfectly. And I even put the gasket on the UIM using sealer and checked it, then attached it to the LIM and looked up from below.

[montessgtp]

And I even put the gasket on the UIM using sealer and checked it, then attached it to the LIM and looked up from below.[/quote] What the hell? What exactly where u lookin for... if the gasket isnt match the surface LOL u wont see it anyway... The whole point of gasket matching is to make the surrounding metal atleast for to the same size of the gasket... So what u did aaron was pointless ,unless im not understanding this.

[SappySE107]

Ok, now lets see, all those that think that is gasket matched stock, raise your hand. Now, all those that think this is bullshit and not even close, raise your hand.

The lower intake to head is not even close, the lower intake to gasket, not even close, and the plenum to lower is as you can hopefully see, not even close. Gasket matching doesnt cause leaks, thats fucking stupid. It wouldnt be gasket matching if you cut the gasket, that would be porting beyond the gasket. Even then, you can use some super sure tack on the gaskets and they wont leak unless you have boost maybe.

[SappySE107]

As for the original post.

I use a marker as well, seems to do ok for me. You will want to match the lower to the plenum, and go at least 1" in on both to blend it in. You can open them up more if you like, the lower has plenty of room for improvement. You aren't looking at much for gains past a gasket match but if you have the time you can do a better job than that.

[RednBlack]

Gasket matching a gasket to stock manis won't do any good, it will just cause leaks.

Jeez! People have been doin this forever! Nice pic Ben! Here's how.. http://www.sa-motorsports.com/diyport.htm And you don't need to buy the kit. Most of it can be done with a Dremel. (anything you need is at Home Depot or Lowes) I use a 45,000 rpm air die grinder. But that's cause I have the stuff for work. Dremel takes longer, but if you are inexperienced, probably the best way to go. One thing that needs to be emphasized, DO NOT!! be too aggresive. Get prussian blue and use it a lot.

[grandprix34]

When I put my gasket on my plenum, i have some pretty bad castings like the pic above. Its just a side project to give me more experience before a pair of heads get here I will port.