head milling

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Here is a chart that gives you an estimate. Its pretty close. I milled mine .030 and lost about 7cc according to the chart it will be about 10.4 cc with open chamber heads

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To use the chart divide the amount to be milled by the number in the chart. Or if you have a particular amount of ccs you want to reduce multiply the amount you want to remove by the number in the chart for example say you have 70cc and you want 65 do 5x.0048=.024 that's how much you need to remove. Or close to it. I'm sure there is a better way out there but that's how is did mine. I wanted to remove 6ccs which was .288 so I just did .030 and it came out to around 7ccs
 
Thanks everyone. I'm trying to come in at 60 cc so I will go .050 and that should get me close. Yes I will shave the intake side .0475. Heads do have SS valves that are flat on the bottom so that should help a little. Thanks again.
 
What the quote on that mill job? I got a set that needs a clean up and may as well get it to where I want it, as well as the intake.
 
It cost more the more u have them milled. Simply because they have to make more passes to take more off. The intake side is another charge. Same goes with it. Kim
 
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My machine shop can cut up to .020 a pass, so figure it out from there. Then I cut the intake side to keep everything in the right relationship. Evidently there is a wide spread on milling costs per machine shop. I never tried to cheap out on performance builds. You have to do what it takes at your level.
 
66fs said:
My machine shop can cut up to .020 a pass, so figure it out from there. Then I cut the intake side to keep everything in the right relationship. Evidently there is a wide spread on milling costs per machine shop. I never tried to cheap out on performance builds. You have to do what it takes at your level.
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If this is a fresh build, why not leave the heads and intake alone and just use other pistons.
Just spit balling
 
512Stroker said:
If this is a fresh build, why not leave the heads and intake alone and just use other pistons.
Just spit balling
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Heads always "warp" a bit so while you are milling them flat again, I just would go the whole .020. Then mill the intake side .019 to keep the head surfaces in the right relationship to each other. You only have to do this once as they don't "move" much after all those years and thermal cycles. I never mill an intake manifold, unless it is out of spec. I still have High Performance blocks from 273's, a 318 Magnum, and 340's that will clean up with a hone, so I will reuse the pistons in those blocks. Those engines are not compression challenged, so I do not feel the need to add the extra expense of boring and pistons. I assume the OP is keeping his short block as is or is just freshening up the motor.
 
oldkimmer said:
... Notice how far the bolts are outta wack. Kim
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I don't see a problem, that's not far out.. Sure they are not in the exact centre of the hole but they look like they have been easily started and port matching will need to be done. But if they are all like that the inlet will still bolt down properly. If only 3/4 of the thread was visible through the hole, now that would be a problem and the intake would need to be machined.
 
66fs said:
Heads always "warp" a bit so while you are milling them flat again, I just would go the whole .020. Then mill the intake side .019 to keep the head surfaces in the right relationship to each other. You only have to do this once as they don't "move" much after all those years and thermal cycles. I never mill an intake manifold, unless it is out of spec. I still have High Performance blocks from 273's, a 318 Magnum, and 340's that will clean up with a hone, so I will reuse the pistons in those blocks. Those engines are not compression challenged, so I do not feel the need to add the extra expense of boring and pistons. I assume the OP is keeping his short block as is or is just freshening up the motor.
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I'm curious about the highlighted text.

This sounds like you're saying you mill the intake side of the "head" to compensate for the material removal of the cylinder side. I my head, that would pull the intake side of the head "away" from the intake, causing a gap, no?

What am I missing?

Seriously not a gotcha, I am trying to understand.
 
No, the intake sides get closer as the head if effect gets shorter and makes the V narrower. That’s why u mill the intake sides of the heads or the intake manifold sides. Kim
 
oldkimmer said:
No, the intake sides get closer as the head if effect gets shorter and makes the V narrower. That’s why u mill the intake sides of the heads or the intake manifold sides. Kim
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See, here is where that doesn't seem right to me.

Looking at the pic below, the intake side of the head leans back toward the head side of that mating surface. Moving the head down shouldn't result in a narrower valley, but it will move the intake port down, which would require all three lower surfaces on the intake manifold to be cut to make the intake ports line up

Cutting the bottom of the intake manifold then would require the intake side of the manifold to be cut to make the intake sit lower to match up with the new "lower" location of the port side of the head.



rscb1.jpg
 
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