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i have stock heads and i wanted to build the compression on my motor to increase the horsepower. how much should i mill the heads. the heads are already off the car so thats not a problem. i have a full exause no cats trickflow intake cold air and a 306 bottom end.
any input is greatly appreciated thanks
 

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I personally would not mill them past about .050"- .060" because the stock production cast iron heads are like the stock production blocks. Thin wall castings! ;)
Especially if you plan on forced induction or nitrous oxide use in the future.
Head gasket life will more than likely be an issue because the deck surface could flex due to excessive milling.
 

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with .030" taken off mine I have 58cc (average) chambers after polishing them....this is with d0oe 351 heads though

e7's are 62-64cc to begin with
 

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Don't forget, whatever amount you mill them -- the geometry of the sealing surface with the lower intake and alignment of intake ports changes, your piston to valve clearance changes, and you may need shorter pushrods as well. Depending on your engine, it may not be as simple as just milling the heads.
 

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I would also keep in mind that if you mill them to much you may need longer pushrods, and you can't run as much timing. I wouldn't take them down more than about .020-.025. As long as you have them off, why not take a cartridge and clean up that EGR bump?
 
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