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kstylianos kstylianos is offline
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Join Date: Nov 2002
Location: Arlington, VA
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Early 80's SC's have a stated stock CR of 9.3:1. If you do the actual measurements, stock CR usually measures about .25-.50 lower. Nonetheless, if you start with the stated 9.3:1 and remove .25 from the heads, this will drop your head volume from ~90cc's to ~87.5, increasing the compression ratio to about 9.66:1. Remember also, not shimming the cylinders will bring your piston/head and piston/valve clearances .25 closer as well. Do your measurements to make sure all is well.

The above was calculated assuming bore-95mm, stroke-70.4mm, deck height-1mm, cylinder head volume-87.5cc, and piston dome volume-37cc. Itís probably in your best interest to do these measurements and calculate your actual CR.
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Charlie Stylianos
1982 SC Targa
www.Dorkiphus.com - (The Land of the NoVA/DC/MD Porschephiles)
Old 06-21-2005, 04:29 PM
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