I've only torn apart two engines this far; one was going through a rebuild and the other at a JY, so take this with a grain of salt, but couldn't you just take a rubber mallet to give it a little encouragement? The 2.3 is a non-interference engine, after all, so it not being at TDC shouldn't matter. If you don't want to do that, try using a few plastic putty knives to pry into the head/block mating surfaces at multiple locations to break the seal. Whatever you decide, good luck!