You could fit a new timing chain and oil pump rotor while you have it all torn down, and if the water pump is original then that could be retired and the thermostat with it.
Use the composite head gaskets rather than the tin ones on a rebuild, and make sure that the faces are scrupulously clean before reassembly.
When you assemble the heads back to the block, get the inlet manifold in place but with just four bolts holding it to the heads, with the original gasket in place. Nip the bolts up to half tight then go through the head pulling down sequence. The inlet can be removed now and new gasket fitted. It aligns the inlet and heads nicely to each other and saves stresses being set up.
The heads have a lot of leeway to move, even though they are dowelled to the block.
Peter