I am rebuilding a 2.3 liter disi turbo engine for CX-7 , I purchased pre-2010 short block that I have put new rod bearings etc in. I say that because it has the older style dished pistons. Why did Mazda change the pistons to the deeper more pronounced dish in 2010?
It appears that Mazda uses the same cylinder head throughout these years. My question is can I use the head with the pre-2010 pistons on my rebuild .

 

i think you are asking a question in an area of minium experience

 

To do a head or piston swap from different year engines after confirming all bolt on parts to the head i.e manifolds,sensors etc. you must do the MATH.

You would need to know both cylinder heads chamber volume in cc. You will need to check for any changes in camshaft specifications. You will need to check the cc volume at Top dead center between the pistons you intend to use and what originally was in the engine. Most likely they will not be the same so your final compression will depend on several factors. The head gasket compressed thickness(after torquing), the volume of the pistons at top dead center based on the deck height of your short block you are using. If you do not get the same final compression ration you will have problems.