I will use flat top pistons not domed ones, so I can use a closed chambered head??? It is standard deck height right now but hasn't been checked and surfaced yet.
The style of piston (flat top or dome) doesn't matter. What matters is where it sits in the block and that is determined by the pistons compression height and the actual deck height which varies from block to block. Aftermarket pistons can be found in different compression heights. If you want to run closed chambered heads you need to find a piston that doesn't stick out of the block or you'll have to run thicker head gaskets to get the piston to head clearance you need. Generally speaking .040" is enough piston to head clearance. Also keep in mind that when swapping to a different piston that the rotating assembly will most likely need rebalanced.