| 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 |