Milled/shaved 243 heads
Thread Starter
Drifting
Joined: Sep 2009
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From: cinnaminson n.j.
St. Jude Donor '14
Milled/shaved 243 heads
I just bought a set of ls6 heads. Is there an easy way to tell if they have been shaved? Is there an easy accurate way to cc the chambers? I would like to get 11-1 compression. I don't want to hurt airflow. I have read a lot of good things about the stock head gaskets. Is there any reasonably priced .040 gaskets that are reliable? Thanks in advance for your help.
AMP Racing
Joined: Aug 2006
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From: Washington TWP NJ
2023 C5 of the Year Finalist - Modified
2017 C5 of Year Finalist
St. Jude Donor '09-'10-'11-'12
if they're milled, the shop that did it likely stamped how much they were milled on the head.
Cometic makes a .040 gasket
Cometic makes a .040 gasket
Thread Starter
Drifting
Joined: Sep 2009
Posts: 1,719
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From: cinnaminson n.j.
St. Jude Donor '14
Do anyone know from experience how much can safely be removed from head/ gasket thickness before fly cutting pistons is needed? I will be using an eps 222/226-.597.598 113 cam. I would rather not cut the pistons but I will if necessary.
Melting Slicks
Joined: Apr 2012
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I'm running Cometic .40 gaskets on 64cc (stock) ported and polished 243's and the setup has been great. I'm just under 11:1 (I think 10.95:1 or so). As far as I know, to CC the chambers you'll have to get with a machine shop that can perform the measuring.
AMP Racing
Joined: Aug 2006
Posts: 10,754
Likes: 589
From: Washington TWP NJ
2023 C5 of the Year Finalist - Modified
2017 C5 of Year Finalist
St. Jude Donor '09-'10-'11-'12
That said, I had a cam with more lift and duration in my LS1 and milled .030 with plenty of room. I'm not a cam expert by any means. There is possibly a mathematical equation that can tell you just about how much room you'll have.
I had D&F in Berlin do the head work for me. They're great guys over there.
Melting Slicks
Joined: Apr 2012
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I echo capthuff here, you have to measure to be sure, but with that cam, I think you could get down to a 60 or 61 and be safe. Couple of things to remember:
1) Milling- every .006 is 1cc of chamber.
2) The .040 gasket will add quench, which is GREAT to protect against detonation, and being that it is thinner than the GM gasket (stock gasket is .058), it performs like a milled head minus the loss of flow milling a head will do.
3) as mentioned above, milling a head will reduce flow, so, if you mill your heads, you will reduce some of the flow you gain from porting and polishing your heads.
4) if you're doing a a full head and cam swap my .02 is keep all the top side of the head stuff light as possible - i.e. valves, springs (beehive if possible), rockers (trunnion upgrade the stockers is best) - and make all the lower head stuff stout - i.e.- lifters, pushrods.
Light on top will give you the best power, stout and heavier on the lower stuff will keep you swap reliable. Just my .02
1) Milling- every .006 is 1cc of chamber.
2) The .040 gasket will add quench, which is GREAT to protect against detonation, and being that it is thinner than the GM gasket (stock gasket is .058), it performs like a milled head minus the loss of flow milling a head will do.
3) as mentioned above, milling a head will reduce flow, so, if you mill your heads, you will reduce some of the flow you gain from porting and polishing your heads.
4) if you're doing a a full head and cam swap my .02 is keep all the top side of the head stuff light as possible - i.e. valves, springs (beehive if possible), rockers (trunnion upgrade the stockers is best) - and make all the lower head stuff stout - i.e.- lifters, pushrods.
Light on top will give you the best power, stout and heavier on the lower stuff will keep you swap reliable. Just my .02
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Safety Car
Joined: Aug 2011
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From: Portland OR
I echo capthuff here, you have to measure to be sure, but with that cam, I think you could get down to a 60 or 61 and be safe. Couple of things to remember:
1) Milling- every .006 is 1cc of chamber.
2) The .040 gasket will add quench, which is GREAT to protect against detonation, and being that it is thinner than the GM gasket (stock gasket is .058), it performs like a milled head minus the loss of flow milling a head will do.
3) as mentioned above, milling a head will reduce flow, so, if you mill your heads, you will reduce some of the flow you gain from porting and polishing your heads.
1) Milling- every .006 is 1cc of chamber.
2) The .040 gasket will add quench, which is GREAT to protect against detonation, and being that it is thinner than the GM gasket (stock gasket is .058), it performs like a milled head minus the loss of flow milling a head will do.
3) as mentioned above, milling a head will reduce flow, so, if you mill your heads, you will reduce some of the flow you gain from porting and polishing your heads.
Also, a given that milling the heads hurts flow?
Ron
Melting Slicks
Joined: Nov 2008
Posts: 2,938
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From: Rochester Hills MI
here's what you do if you want to measure the volume of the chamber in the heads:
with the valves in place, clean the chamber and very lightly lubricate it. pack it full of clay without any air bubbles, and you can use a putty knife to make sure the top of the clay is coplanar with the mating surface. fill a graduated cylinder with water, and take note of the measurement. remove the clay and roll it up with no bubbles so it will fit in the graduted cylinder. drop it in the gradutated cylinder. subtract the first measurement from the new measurement, and you have your chamber capacity.
you can also use a piece of plexiglass with a hole drilled in it. clean the mating surface, and put the plexiglass over the chamber. fill a graduated buret with water keeping track of how much you are putting in, and fill the chamber until there arent any bubbles. add up your measurements, and you have the capacity.
with the valves in place, clean the chamber and very lightly lubricate it. pack it full of clay without any air bubbles, and you can use a putty knife to make sure the top of the clay is coplanar with the mating surface. fill a graduated cylinder with water, and take note of the measurement. remove the clay and roll it up with no bubbles so it will fit in the graduted cylinder. drop it in the gradutated cylinder. subtract the first measurement from the new measurement, and you have your chamber capacity.
you can also use a piece of plexiglass with a hole drilled in it. clean the mating surface, and put the plexiglass over the chamber. fill a graduated buret with water keeping track of how much you are putting in, and fill the chamber until there arent any bubbles. add up your measurements, and you have the capacity.
Melting Slicks
Joined: Apr 2012
Posts: 2,596
Likes: 6
And yes, shrinking the chamber adds compression, but does cut just a little air flow.