Ah, ok, that makes sense. So some work would be required to match up the channels for say an EJ20 gasket to work along with the EJ18 block, but the bolt locations are identcle... I would think that the larger EJ25 heads would have trouble bolting up with smaller blocks though, as the pistons are much smaller than the ports, but I dont know that much about the specifics and thats why I'm asking for details so I can learn more
But would you think it would be possible to modify either the EJ18 block or EJ20 heads to fit better with either an EJ18 gasket or EJ20 gasket (depending on which one has better flow)?
And ya, the EJ22's are different motors, but I havent seen anything to show that an EJ20 isnt a bored out EJ18 yet