66-67 Dodge Charger Source Guide

Compression Ratio Calculator

Posted by Robert Spelic on 12/15/05

Here is an excel spreadsheet I developed to figure compression ratio. Do with it what you want.

There is one sheet that has various engine specs that I have looked up for various rods and piston combos. There is a sheet entitled “compression” that will calculate the ratio if you enter the data into the top area of the sheet.

I populated it with stock 440 sizes and the .07 figure that Cory indicates that the stock piston is down the hole.

That works out to a compression height of about 2 inches and a compression ratio of 9.04 with 82cc Edelbrock heads. Actually that number sounds more like what I would have expected to see. Most of the Ross pistons are .017 down in the hole and I originally worked from something around that number.

Bob in Pittsburgh

Compression Ratio Calculator