Ported Chevy 487x heads

[Carnut1]

Go back on the valve and try a 55 angle about .010-.015 wide just at the seat line on the edge of the valve. Then go to the chamber edge and break that edge with a flapper wheel. Tell us what it does with that 1204.

I just reread this and I realized you are talking about a 55 degree angle on the valve itself. That is why it is so narrow. I thought you were asking for 55 degree seats. My mistake.

[mag2555]

See, I told you , about 175 CCs!

Thanks for taking the time to do the pour!

What is the valve bowl throat size up to Percent wise?

[Adger Smith]

Yes, work the valve with the top angle and chamber side radius. Yes the X casting is usually 10 CC bigger in the bowl area. tale out a little of the guide like you did and do some pushrod pinch opening and you get to the 175 CC range. I like the finish you have left on the port. Back in the Day when I did a lot of these for Circle Track racing a finish like that seemed to help throttle response. You might get rid of a little of the high lift swirl by laying back the chamber into the Quench pad at the outer edge of the intake to chamber side. Another way of taking out swirl is putting a little bias in the SSR floor. It might pick up a few points at high lift.
http://www.speedtalk.com/forum/download ... &mode=view The upper left portion in this picture. Dip it back past the top cut on the valve guide C/l to the intake cylinder wall side.

[Carnut1]

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little chamber work. Intake top left corner.

[Carnut1]

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basic port layout.

[Carnut1]

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Flow after minor chamber change.

[Carnut1]

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Not thrilled with old valve job. Quick guide hone and vj touch up.

[Carnut1]

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Add 30 degree backcut.

[Carnut1]

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My Sioux 2001 does not adjust to 55 degree valve angle so this is as steep as it would go. Aprox 50 degree .015"

[Adger Smith]

Looks like it was starting to work, in the mid it did take the top off a number or two and it did some correction to swirl.As you loose swirl it should pick up a little flow. Shame you couldn't have got the full 55 on it. Some times it is a winner sometimes it is not. Like I said I've never done it with a full radius valve job. (that cutter)
Just have to test it.

[Carnut1]

Looks like it was starting to work, in the mid it did take the top off a number or two and it did some correction to swirl.As you loose swirl it should pick up a little flow. Shame you couldn't have got the full 55 on it. Some times it is a winner sometimes it is not. Like I said I've never done it with a full radius valve job. (that cutter)
Just have to test it.

I don't have cutters. Only old Sioux stones that I can shape to a radius.

[Bob Hollinshead]

good stuff, thanks for sharing the results of these little changes. I had a set of 487X heads on a little 355/6-71 blower motor that seemed to work fairly well.

[Adger Smith]

Like I said: I've never used that angle technique with a full radiused seat. I've only used it on multi angled seat cuts. On some BIg diameter valve/port combinations it doesn't work at all. It would be interesting to see what the change on your heads would be with just a 52 or 60 about .080 - .100 wide on the bottom side of your wide seat.
I have a radiused cutter I had built with a 60 on it to do that cut. I use it on some ex. It seems to pick up low - mid lift numbers. I've used it on lift limited heads to help with ex blow down. I've never been able to do actual tests on it, but I think it might help from having to put too much cam duration on the ex.

[Carnut1]

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Since this port looked so horrible in pictures I spent a few min bringing the gasket match a bit better and removed the ridges from the roof and added a small 70 degree cut under the 60.

[Carnut1]

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Cleaned up port final flow test. I would guess 178 cc port at most. Damn close to AFR 180 street heads without the good chamber.