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5.3 vs 243 Heads...Confusion

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Old Jun 2, 2007 | 05:28 PM
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i believe over on tech someone was saying .006"=1cc for the 243's. which should mean in the neighborhood of .032-.036".
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Old Jun 3, 2007 | 12:53 AM
  #42  
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Originally Posted by Okie5.3
i believe over on tech someone was saying .006"=1cc for the 243's. which should mean in the neighborhood of .032-.036".
It wasn't a guess, .055" for a 60.9cc chamber:

http://www.sdparts.com/product/88958...ccChamber.aspx

"Best buy on the planet! Unbelievable performance from fully CNC ported cylinder heads. Some of the best low and mid-lift numbers we have ever seen from a stock size valve. These heads will flow over 200cfm at 0.300" lift and 290+ at 0.500". Fully assembled with the 2002 Z06 light-weight valves and the new "02 valve springs. These heads have been milled 0.055" to bring the combustion chambers back down to approximately 60.9cc. Care must taken to check pushrod length and proper intake installation when using these cylinder heads. Price is for each cylinder head"
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Old Jun 3, 2007 | 08:15 AM
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Originally Posted by silent1
It wasn't a guess, .055" for a 60.9cc chamber:

http://www.sdparts.com/product/88958...ccChamber.aspx

"Best buy on the planet! Unbelievable performance from fully CNC ported cylinder heads. Some of the best low and mid-lift numbers we have ever seen from a stock size valve. These heads will flow over 200cfm at 0.300" lift and 290+ at 0.500". Fully assembled with the 2002 Z06 light-weight valves and the new "02 valve springs. These heads have been milled 0.055" to bring the combustion chambers back down to approximately 60.9cc. Care must taken to check pushrod length and proper intake installation when using these cylinder heads. Price is for each cylinder head"
But what you are missing is that when the chamber of a head is ported (as in this "fully CNC ported" example), it gets larger. So it takes some milling to get them back to 65cc after the porting, and then even more to bring the chamber size down.
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Old Jun 3, 2007 | 08:17 AM
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Originally Posted by Okie5.3
i believe over on tech someone was saying .006"=1cc for the 243's. which should mean in the neighborhood of .032-.036".
Hah, never thought of looking on tech. I guess that place can be good for something.

Where you been Okie? Get any of those new parts on yet?
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Old Jun 3, 2007 | 11:35 AM
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Originally Posted by tdrumm
But what you are missing is that when the chamber of a head is ported (as in this "fully CNC ported" example), it gets larger. So it takes some milling to get them back to 65cc after the porting, and then even more to bring the chamber size down.
Agh! Very true, my apologies.
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Old Jun 3, 2007 | 08:33 PM
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Originally Posted by tdrumm
But what you are missing is that when the chamber of a head is ported (as in this "fully CNC ported" example), it gets larger. So it takes some milling to get them back to 65cc after the porting, and then even more to bring the chamber size down.
guess i should have qualified my statement...on an stock unmolested 243 chamber .006" = ~1cc.

Originally Posted by tdrumm
Where you been Okie? Get any of those new parts on yet?
hey tom what's going on? haven't had a chance to do much of anything lately, work has been keeping me hopping for the past few months. if you want to know the truth, it's more procrastination than anything. now that it looks like the rain has finally stopped i guess its time to get on with it.

if your tired of those junky old WCCH heads i'll trade ya out for some stock 243's and 5.3s. you might have to kick in a little $$$ for the trade though...
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Old Jun 4, 2007 | 06:55 AM
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Originally Posted by trever1t
Hmm, are the 799 castings chambered / valved differently for the 5.3's than the LS6's? Are they that hard to find?
there's a few 799's on ebay currently.
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Old Jun 4, 2007 | 07:02 AM
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Originally Posted by Okie5.3
if your tired of those junky old WCCH heads i'll trade ya out for some stock 243's and 5.3s. you might have to kick in a little $$$ for the trade though...
LOL, "junky". After what I went through the first time swapping heads, I'm not ever going to take them off again.

sent ya a pm as to not ***** up this thread.
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Old Jun 6, 2007 | 02:53 AM
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whats diffrent from 243's and 799's???
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Old Jun 11, 2007 | 09:55 PM
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Would it not be easier since the price of heads have come down so far for these motors to just buy a set of Patriots or AFRs? I am not trying to be a smart *** just wondering if these stock heads worked are that good or if this is a good way to save a couple hundred bucks or so. I have a friend that will give me a set of LS1 heads....if these are that good I might consider it.
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