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Discussion Starter · #1 ·
Does anyone know the compression difference between a CP uncorrected piston compared to a corrected one? I have a 12:1 uncorrected and it sits roughly .050" in the hole. What would the true compression of this piston be without decking the head?
 

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Discussion Starter · #3 ·
Thanks Bo. That will work out justs right with a +5 stroke for a pump gas build. Does the math hold true if its a 105 bore? And if i decide to up the compression by decking the head then i'll have to adjust the timing to compensate won't i?
 

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OK, by the math.
If you have a corrected deck height 105mm 727 piston thats a true 12:1 at .010" in the hole then if an uncorrected piston is .050" in the hole it will be 10.7:1
If you throw a 5mm crank in it goes to 12.6:1 corrected and 11.2:1 respectfully.
If it was me I would mill the cylinder .040" and have a local automotive machine shop mill half the dome off. This would make more power than leaving it alone with the same octane fuel.
 
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