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Old 11-25-2004, 08:35 PM
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First Attempt At Porting

Ok guys, here's some pics of my first try. Pretty much just gasket matching, but did end up removing some meat. Let me know if this passes muster or any advice. Tnx!

Before (can u tell?):


After:

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Old 11-25-2004, 09:11 PM
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porting

It looks like you have the general idea of port matching, just dont open up the intake port like that, leave it stock, unless there is casting flash in the runners. I am concerned about the intake gasket you have as it appears to be too short for your port, even before you worked on them.

I am referring to leaving the port in the intake manifold, leaving it stock. What that does is makes your head port work like a funnel with the intake manifold port feeding inside it much like a garden hose stuck into a funnel.

The reason for doing it this way is that there could be minor port misalignment from the factories, and if you open the intake port out the same way, you will just duplicate the misalignment. Often what happens is that the ports may overlap each other on one side or the bottom or the top, and this creats a reversion or restriction in the fuel air flow.
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Old 11-25-2004, 09:14 PM
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I'm curious, do you have the valves out of the head?
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Old 11-25-2004, 09:16 PM
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Looks good to me. I usually take out that little bump you see that is cast for the valve cover bolt. The next thing you need to do is a bowl cleanup. Port matching does help somewhat, but the real power is in the bowl cleanup and short side radius smoothing on stock heads. Basically you want a smooth transition from the bowl area to the valves. You will see it is anything but that in factory finish. You can expect 20-30HP at least with the bowl cleanup. Take your time and be careful not to nick the seat. If you do, you will need another valve job.

Chris
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Old 11-25-2004, 09:47 PM
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NXS... The valves are in. which is why the paper towels are crammed in there. I pulled them out with the shop vac going and there's not a spec in there.

Max... Txn for the info. The gasket seems to be the right size. With all the play in the bolt holes, I think I moved it down too far. I didn't take any material off the top, and not all that much off the bottom, as the pic would indicate. Does look strange in the pics though.

Turbo... Tnx. I was wondering how far I could go with those bumps. I think I will take more off. I was thinking that the bottom area of the port was the most critical, so didn't push my luck. The valves have been replaced with 2.02/1.60 and they did a great job of unshrouding. The transition looks pretty good to me, but then again, I'm a rookie. The last thing I need to do (I think) is pin the rocker studs. Just not sure what size roll pins (spring pins?) to use, or how far down I should go.

BTW, these are 434 castings. And yeah, I've read the stories after I got them... Maybe the extra work will help.
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Old 11-26-2004, 06:00 AM
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You want to put the pins as far down in the boss as you can and still get it all the way through. 1/8 inch should be fine to use, but there are kits made that come with the drill and pins for about $10. I am sure summit or jegs carry them.

BTW, unless you paid for it I am sure the bowls are still rough. It takes a good 8 hours to do a bowl job so I am sure you would have known it when you paid if they had done one.

Chris
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Old 11-26-2004, 07:02 AM
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Re: porting

Quote:
Originally posted by Max Keith
....I am referring to leaving the port in the intake manifold, leaving it stock....
MK,

I just want to make sure I understand what you are saying. What 69Vette has done here is good on the "head" side just don't do it on the "manifold" side. Leave that side stock. So, in effect, it's not really port matching - head to manifold, it's port matching - head to gasket. Is that about right?

Dewey

Quote:
Originally posted by TurboS10
...The next thing you need to do is a bowl cleanup. Port matching does help somewhat, but the real power is in the bowl cleanup and short side radius smoothing on stock heads.
Chris

Hey Chris,

For those of us who have not done this before, could you explain (or pics would be even better) exactly the areas you are talking about...and how you get access. Do you remove the valves and go in from that side? If so, does it require a special tool/grinder? Actually, a nice little tutorial on head porting would be great.
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Last edited by cboy; 11-26-2004 at 07:02 AM.
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Old 11-26-2004, 07:30 AM
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first porting

Exactly, the reason for port matching is to alleviate the problem of port misalignment. If you were to go back and flair out the intake runner port as was done with the port in the head, you stand a chance of recreating any of that port misalignment. Im not saying you shouldnt do any work on the intake manifold ports, but you dont want to chamfer them out like you did with the head port. Leaving the runner port slightly smaller just insures that you will not have any port misalignment.
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Old 11-26-2004, 07:39 AM
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See if this link makes it clear: http://www.chevyhiperformance.com/techarticles/95518/

If not, ask any Q's you have.

Chris
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Old 11-26-2004, 07:44 AM
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pinning rocker arm studs

You can go to your nearest hardware store and get 16- 1 to 1 1/2 inch long roll pins for less than $2, and a couple 1/8th inch drill bits for about $3.50- 4. Ive used pinned studs on all my small block Fords, exept for the ones with pedestol rocker arms. Save yourself a couple dollars. Drill into the stud boss from the intake port side.
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Old 11-26-2004, 08:05 AM
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This was an old practice head but it gives an idea. Even with my brothers 1st try this port would give you enough for a seat of the pants feel.
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Old 11-26-2004, 08:53 AM
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Good link TurboS10. I'll have to spend some time reading the detail - but that article will probably answer most of my questions.

NXS, very good shot. They say a picture is worth 1,000 words and yours did it. One small question. I can't read the writing in red which may deal with this, but is it also a good idea to try to clean up that entire area beyond the valve seat itself? I guess that area is what was referred to as "the bowl". Do you smooth off as much of that as you can or do you only do that collar area adjacent to the seat?
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Old 11-26-2004, 09:11 AM
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The red says: This lip needs to be

When you port you can open it up and polish it beyond what the pic shows. That is just a basic cleanup and grind per grind it will net you the most power.

You can also bring the valve guide down to a smooth transistion to the valve stem.

Next would be to open all of it up but you really need to understand flow to do that.

Use your finger to feel all of the port for any inconsistancies and smooth and blend them. Do not have a port that goes from large to small to large. Also try to keep a 3/8 to 1/2" straight down shot at the valve

Of course a polish is very nice but the power benifits are not super great...but nice nonetheless(better for the exhaust port). This particular head is pretty smooth and I personally would not polish...but if you want to beautify it by all means.
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Old 11-26-2004, 09:32 AM
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first porting job

When you port out your intake ports, dont polish them but leave them with a florentine finish. Extensive testing has shown that polishing the intake ports and runners will cause fuel to become unsuspended from the air mixture and return to liquid, causing severe losses in power. I dont know all the ins and outs of laminar air flow, but the gyst of it is that the intake port needs that little bit of roughness to keep the fuel and air mixed properly. However, on the exhaust side, you cant get it shiny enough. Since there is no mixture to keep suspended, the slick surface aids in allowing the exhaust to travel with less restriction, and the polished surface also aids in preventing deposits (carbon) from building up in the ports, and causing performance deterioration.
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Old 11-26-2004, 09:32 AM
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That is a good pic. You cant really see the short side radius, but it is a good place to clean up. What you will see/feel is a ridge on the floor of the port where the air turns the short side to enter the cylinder. You want to smooth this radius. What I do is make one fairly deep cut right at the top of the ridge so the ridge is now a flat spot. Then make two more cuts along the smaller ridges created by the flat spot just created. So then you have three small flat cuts that have greatly smoothed the short side radius of the port. Then I go back and lightly blend the whole area so all the flat areas are gone and you have a smooth transition and turn in the port. Last is to touch the whole area off with a 40 grit sanding roll.

Before you start this you may as well invest in a couple of good carbide cutters for your die grinder. Trying to use the cheap cutters or stones will only serve to piss you off. A carbide cutter will do many sets of heads. The cheap cutters will do about one port each, so the cost is about the same for one set of heads. If you do another you are saving money by getting good tools up front......sound similiar to most hotrodding adventures.

Chris
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