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conig
Dodge Dakota
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3/11/2002
13:32:21
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 Subject: cw- decking heads/mached gasket of 4.7l
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CW or Duner how thick is the gasket on the 4.7L?
I have heard of machining gaskets, those that are thick enough to increase an engines compression.
I've also heard of getting heads decked a couple hundreds of an inch to increase compression, how much does this cost? would it be worth it on the 4.7 l?
all info appreciated.
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Art
Dodge Dakota
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3/11/2002
14:01:23
| RE: cw- decking heads/mached gasket of 4.7l
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You have your termanolgy mixed up,the thicker the head gasket the less compresion you will get and decking is for the block to true it up and only do this if you absolutely need it,it changes the whole engine geometry and what you are talking about on the heads is called milling them down,we usually just clean them up and get a clean and true surface,yes you can mill up to .060 for compresion increase but it all depends on your piston to valve clearances,anyone know if the head bolts on the 4.7 are tourqe to yeild? meaning a one time use head bolt
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Duner
Dodge Dakota
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3/11/2002
14:15:57
|  Not worth it
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I don't really know how much material you could safely remove from the block mating surface of the heads before it started to alter your cam timing. As you change the dimension between the cams and the center sprocket, the timing changes also. One cam would be advancing while the other would be retarding. This would probably offset any gains you could get from the higher compression. So in other words..... I don't think I'd even bother.
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CW
GenIII
3/11/2002
14:46:59
| RE: cw- decking heads/mached gasket of 4.7l
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Also with a aluminum head you don't want to remove much material. Makes them weaker. I don't think you can remove very much at all The service limit on those heads are like .004" or .005". If you want more compression get pistons.
2001 RC 4.7 5sp 9.25" 3.92 LSD
Ported 68mm TB, IAT adjuster, 3" flowmaster cat back, TPS @ .76V, 4" cold air, Roadmaster active suspention, Removed Third cat, Electric fan Convertion, HO cams.
Working on adjustable fuel pressure with return.
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conig
Dodge Dakota
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3/11/2002
19:26:31
| RE: cw- decking heads/mached gasket of 4.7l
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Dam I didn't think it would work, I was toying with the idea of getting the h.o. cams, and figured I'd get a little more compresion and port the heads while I was at it.
I don't think I could install the cams myself so I figured it be cheaper to do all at once.
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