Got this far last Sunday evening. It's on hold for another week while I have other stuff to do. I had to unbolt (see: shear off bolts) downstream exhaust to slide the catalytic converter back enough to reach the last two exhaust manifold bolts. Now that it's out, I am thinking about trying to install the exhaust manifolds on the heads and then put the heads on the block. The cat-to-manifold nuts/bolts are easy to get to.