You would be right except for one problem: You can't make huge increases in bore size, the block usually won't allow it. For example, most small block Ford blocks can only be bored .060" oversized (4.060" vs.
Now rotate the comination to top dead center with the increased stroke and longer rod. This is solved by changing the pin location in the piston.In addition, if a block is bored to the limit, it cannot be bored again after that! It's relatively easy to get out the grinder and grind away parts of the crankcase, notch out the bottom of the cylinder walls, buy a different oil pan or pickup, or buy a different main cap girdle.Most people will want to save a little room for freshen ups or rebuilds. But you can't exactly clearance the camshaft now can you?You have heard some people talk about a "zero deck engine".This refers to the deck clearance of the engine being zero (i.e.There are other things to take into account like camshaft specs, head flow, and a myriad of other things.Without getting too detailed, you need to understand that not all components that work well for a 302 cubic inch engine work best for a 331 cubic inch engine or a 347, or a 354, etc.This dimension is called the "compression height" of the piston. While changing the compression height by itself would alter the compression, it is not the "ideal" way to change the compression if that is what you wanted to do.The location of the pin in the piston is really dictated by the stroke and rod combination you are attempting to build instead of the compression ratio you want.Imagining all of this, you should start to understand the limitations associated with moving the pin around and lengthening the rod.This is where the deck height of the block comes into play.