[dk01_99]

ok me and my dad have been talking about this for awhile and we havent been able to come up with the answer. it may sound like a dumb question but oh well..... how exactly do you change the compression of a motor by just changing out pistons? if you raise the piston height then its gonna compress into a smaller area but its not gonna be taking in as much air because the piston wont be going down as far correct? so this in return doesnt exactly change the compression ratio does it? hopefully this if enough info on what im trying to ask..... later

[KULTULZ]

You are confusing swept volume with quenched volume. You raise cylinder compression ratio by making cylinder volume smaller at combustion, via pop-ups, milling head combustion chamber/block deck height or different volume (thickness) head gaskets. Even excessive carbon build-up in the cylinder will raise compression ratio.

I think I explained that right... <img src="confused.gif" border="0">

[woodz428]

Plus, even if you raise the top of the piston, it still moves down the same distance but has less area to compress it into.

[kurley]

Plus, you have to be careful not cut the head or the block to much or the piston will kiss the head. plus,you need to check the valve to piston clearance. If either of these happen and you start the motor, it will make a good day, real bad,quick.