I would like to know how to calculate compression ratio. My engine is a standard bore/stroke 1967 327using stock cast flat head aluminum alloy, 4 dimple pistons. My heads are stock '461 castings with a combustion chamber of reportably 62.076 cc's.
The AMA specs rate the 327/275 at 10.0:1. This engine originally had the '462 head which also has the 62.076 cc. Is this a valid compression ratio? What is the formula for calculating compression ratio? What octane gas do I need to keep from detonation?

thanks

Here's a location with that info:
http://www.kb-silvolite.com/page56.htm



[This message has been edited by corvgreg (edited 08-11-99).]

You can download Comp Cams Camquest software from their page for free. It has many utility programs that come in handy as well as a cam selection program. One of the programs calcs CR.

Dave

Save this page and use it offline.

http://www.jersey.net/~rforceno/crs/crs.htm .



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Pat Kelley
66 & 67 El Caminos

Compression ratio is the total volume of a cylinder at bottom dead center compared to the volume at top dead center (including combustion chamber and head gasket thickness).

Thanks guys...looks like I'm at about 9.7....I better start saving for that high octane...

mo.