To add just a little to Bob's excellent description
- The necks where the radiator hoses would attached were masked by likely a slip over mask that kept the paint off of the sealing surface with the hoses.
- Water pump pulley attachment hub was masked also.
- No parts that I think of were painted first then installed and repainted with the engine assembly.
- Oil filter adapter was not installed at time the engine was painted
- Smog tubes and check valves connected to the heads were in place and attached when the assembly was painted
- If you choose the back side of the water pump can be fully painted with a fake "natural" paint prior to installation to protect the surfaces that may not get engine paint
- Borrowed from another posting but an example of the shadow Bob described at the back of the intake manifold. Also the painted and unpainted parts of the PCV vacuum plumbing