i need to know how much to mill from my cylinder head. i pulled it from a junk car, and my machine shop says it has been surfaced. the problem is we dont know if its been milled, or just surfaced. i cc'ed it and came up with 58cc per combustion chamber. how many cc's can i expect to lose per 0.01"? i'm running mopars mild competition cam, so i know i shouldn't mill too much off, or i might have clearance issues. i would like to end up with 9.25-9.5:1 compression to keep it streetable. thanks for any help!

Hi,

Welcome - If you use he Search function you will get all the info you need - there is so much on the topic

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Regards,
Fanie Gerber
It's never junk, it's just a part you're not currently using

http://www.valiant50.co.za
Just say I own a few Mopars

To calculate the compression ratio you need to know not only the combustion chamber size (58cc is close to standard from my experience) but the head gasket compressed thickness and bore, and the engine's bore, stroke and piston deck height. My Valiant's 225 measured out to be 8:1 stock. Another 225 was only 7.7:1.

.0066" off a slant head is 1cc chamber volume.

Mild 225s almost never have valve to piston clearance issues. You'll run out of retainer to guide clearance well before the pistons and valves get close.

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Joshua

Once you get all of your measurements, the Internet is littered with compression ratio calculators.

Danny