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I have a pair of 400 heads (76cc) I am putting on a 350 I am rebuilding. My question is I want to mill the heads down but I am not sure how much is too much. Okay i know what your gonna ask and the answers are; flattop pistons (8.33 comp. rat. 76cc heads) and I am hoping to get close to about 9.25:1. I will be putting on the .016 head gasket to help. I would appreciate any help.
 

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Sounds like a mistake to me. That gasket will be too thin. If it were my engine I would want a thicker, more reliable head gasket.

I don't know how much it will take to mill the heads to reach the compression you are talking about, but I question whether it is worth it. If you are really in a bind it might be worth it, but I think you would be better off getting the right heads to begin with.
 

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If it were me, I would mill the heads .010 and have the block decked .010, I would also use the .028 thickness GM head gasket. Either way you look at this, by using the head gasket you plan to use, the heads and the block must be completely flat, otherwise it won`t seal up too well, this is why most aftermarket gaskets are .041, they make up for some warpness and irregularties on the surface. After you have the block decked, do a mock up assembly and check the quench distance, as long as your below .060 it should be fine, but I also wouldn`t go under .040. A tight quench distance will give your engine a little more throttle response and it`ll run good on 87 octane.
 
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