Static compression ratio is simply a static measurement of the volumes of the cylinder at top and bottom dead center, and is only one factor in running an engine on low octane fuel. How much cylinder pressure actually happens in the cylinder and the cam timing events are much more important. For example I built several engines for some truck pullers several years ago, who had as a class rule pump gas only, I used 14 to 1 dome pistons in those engines, they worked very well. A good engine program will tell you much more about if your combination will work. Their are several, I use performance trends, it will calculate if detonation will be a problem and calculate a timing curve to allow you to make the engine live. When I do a pump gas build, I plug the numbers into the program, get the timing curve, and then set the distributor up in a distributor machine to match, it is in the ball park every time I have done it. I have even used this method to set up initial timing maps for boosted applications with electronic fuel injection. The program allows you to enter the octane fuel and the amount of boost, and it will tell you how much you need to retard the timing through the curve. And with the cost of engine parts and machine work, around $100.00 is a small price to pay, plus it's fun to waste time with on rainy days as well. And with any computer program is garbage in garbage out, you have to take the time to accurately enter the parameters of your engine, wild guesses will not get it. I use Pipemax as well, especially in building headers and picking intake manifolds.