Originally Posted by DrDirt

Sounds like you may not have gotten the head seated properly. I once had a friend who had a leak at the firewall after he redid his heads. Turned out that when he pulled the heads, one of the alignment dowels stuck in the head and one stuck in the block. When he put it back together, he put another dowel in the empty hole in the block. Put the head back on and torqued it down not realizing he had 2 dowels in one corner of the head. That leaves a bit of a crack at the corner.

True story. Check and see if the head is on straight.