Ported Chevy 487x heads

[Carnut1]

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AFR180 flowsheet

[Adger Smith]

Strong .400 number, too. Notice the Swirl doesn't really take off till around .500..
That is good, too. Pretty good for some "old Iron" Just a little back up after .500
I would say good for a .500 to .525 lift cam
It just hit me your .200 -.500 were all better than the AFR 180 CNC..!!!

[Carnut1]

Strong .400 number, too. Notice the Swirl doesn't really take off till around .500..
That is good, too. Pretty good for some "old Iron" Just a little back up after .500
I would say good for a .500 to .525 lift cam

Thanks! I am so surprised. My learning curve since I bought this bench has really changed my views. I have not bolted a 76cc head to anything over 300hp in many years. They aren't as bad as I thought.

[Adger Smith]

When you throw the numbers for the AFR and the 487X heads on a graph you will really see the difference in the .200-500. The shape of the flow curve will indicate more flow where the area of the cam is most, not full lift like everyone is so stuck on. I would rather give up a few points at full lift for a better avg mid lift. It will usually make more power.

[Carnut1]

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487x vs. AFR cnc graph. 487x uses 350 felpro blue head gasket over 4.3" bore 11/32 valve stems. AFR uses 4.06" bore 8mm valve stems.

[Carnut1]

When you throw the numbers for the AFR and the 487X heads on a graph you will really see the difference in the .200-500. The shape of the flow curve will indicate more flow where the area of the cam is most, not full lift like everyone is so stuck on. I would rather give up a few points at full lift for a better avg mid lift. It will usually make more power.

I agree, any time I run a head through a dyno program the head with the better mid lift makes more power.

[vortecpro]

Can you post up a picture of your bore adapter?

[fly442]

years ago I used a set of 487x heads on a 355 Chevy with small domes and a old Gk solid cam. One of the best running 355 I had . Also flow is not everything but that motor out ran a lot of bigger engine,s

[Carnut1]

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Best pic I have of bore adapter.

[mag2555]

Without question better average numbers in the average lift range of whatever Cam makes more power then 8 more cfm at peak Cam lift, the better peak air flow numbers the longer the motor in question will hold onto whatever its peak hp number is before the hp noses over.

The only down side with a 175 cc port over a larger one with the same air flow is the port velocity that can be too high once a given Cam size And or rpm is reached, but up to 5800 rpm a 355 motor will rev in flash and run amazingly well!!!

[Bob Hollinshead]

It would be good to see how these compare to 441's

[Adger Smith]

The 487X will usually have higher peak numbers. The 441 starts with a 10 CC smaller port (approx 162) The X head has a different-larger bowl / roof area.
Takes a lot of hand work to make them get up there.

[Carnut1]

It would be good to see how these compare to 441's

Sure just keep loading the work on. I have a good set of 441's somewhere. They have the 441 on the bottom 90 degrees from normal 441. I am not sure why these are supposed to be the better castings.

[Carnut1]

The 487X will usually have higher peak numbers. The 441 starts with a 10 CC smaller port (approx 162) The X head has a different-larger bowl / roof area.
Takes a lot of hand work to make them get up there.

Give me a week or so, I will compare them. Thanks Charlie

[Bob Hollinshead]

It would be good to see how these compare to 441's

Sure just keep loading the work on. I have a good set of 441's somewhere. They have the 441 on the bottom 90 degrees from normal 441. I am not sure why these are supposed to be the better castings.

LOL, sounds like you have a good collection of heads!