I am just posting this for my buddy to what what everone has to say about this.
My friend has an integra se(ls) and the engine has 50,000km on it with no internal mods. He is thinking of purchasing a B18a head off my buddy that has been port polished and getting 403 cams with springs in it. The head is milled 20 thousand. He was wondering if he puts the head on his engine if it will seal properly(with new gaskets of coarse). His logic comes from the fact that the engine has some km's on it and if it would have warped a bit with the head. If he puts the new head on will the block have a slight warp to it or should it still be straight. He doesn't want to take the block out to have it decked.

 

Im not an engine builder but I have swapped heads between engines before and never had any problems with head gasket seal from the deck or head being warped. I dont believe it should be warped from just normal use, unless the engine had overheated at some point.

 

as sayd above, you should be ok meng

 

Unless he over heated then there should be no prob. He can always check it himself with a feeler gauge and a straight edge. The specs and tolerances are in the service manuel.