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Message: <blockquote data-quote="96blak54" data-source="post: 1324221" data-attributes="member: 14727">So im looking back at old threads and sort of criticizing myself of what I wrote and in this thread occurred to me,...I never stated how to achieve the .020" squish....or less. Lets dig into it!Remember squish is the amount of space between the piston crown and head deck surface when the piston is at top dead center (TDC). The length of rod, the distance from wrist pin to piston top/crown, head gasket crushed, piston rocking in the bore and the material type of each one made, greatly affect the squish distance when into the rpm's....running squish...so to speak.Stock 4.6l modulars nominal(not running) squish distance floats around .045 and doesnt change to much from this measure when running. Stock modulars consist of powdered metal rods and casted hypoeutectic pistons, both of which are known not to stretch or expand greatly when heated and stressed.All types of steels have the ability to expand and stretch when stressed,... return to its nominal state when not, and be completely reliable. Known as tensile.  Cast iron, powdered metal, aluminum have very limited tensile strength, will retain damaging shape when stressed, but will expand when heated just like steel. Knowing these veriables will greatly improve your build.We look back at that stock modular and realize the stretch from the rod when running or expnsion from the piston will be very little, because of their own material make up....Without so much mathmatics and pure speculation, im guessing the factory considers the rods expansion/stretch to be .005" and piston swelling maybe .005"( all because of material make up and stress) putting the squish distance at a comfortable manufacturer stand point of .035" while running high rpm's. Nominal .045" â€¢ -.015" piston deck hight(the pistons             distance down in the hole)â€¢ .030" head gasket crushed= .045" squishTake in the speculated .010" of materials used when the rpm's are high, subtracting from the nominal .045" and you come up with .035". Can we do better? Absolutely! The closer we can get while running safely,  the more static compression we can run, the better auto ignited fuel control mechanically, and detonation resistant it becomes.Their is a rule of thumb used for steel rods stretch/expansion. For every inch of rod concider .002" for stretch. For forged pistons consideration we mathmatically derive the amount but bore size and compression distance affect the outcome. And then the gasket thickness when crushed. Take these veriables in your build and up that compression!!!</blockquote>