Valve check and coolant pipes

[Mustang]

I did mine a couple winters ago. The coolant pipes were pretty bad, pinholes under the rust so I remade them with chemical metal. New o rings definitely. I had a good few out of spec so you might need shims.  I took the opportunity to remove all the water pipes and refurbished them and new seals too. You need to drop the coolant and the oil if you do the other lower pipes.