listen to what Richard said there, he knows what he's talking about..... now that you've learned about compression a little bit..... lets get some of the basics from you, what kind of car are you building? what is the main purpose of this car? what kind of budget are you currently looking at for building a motor?(that can be a very tricky question especially if you're married )

please feel free to ask all you want about engine theory the more you know on how everything works, the more it will make sense to you when you start turning wrenches