What advantages are there to painting the inside of the block?

I have a virgin 5.9L block that is NOS from Mopar Performance. I thought about doing the Glyptal coating because the only oil the block has ever seen is for storage and corrosion resistance. Moreover, I was thinking about getting the block stress relieved in an oven. If my new machinist has the equipment I would get it stress relieved and paint glyptal.

@Demonracer actually answered a question that I had; Will baking a used block be enough heat to effectively make enough oil leach from the cast? Sounds like it. Off topic thought now is, would a virgin block NEED to even be stress relieved for a 5-700 horsepower engine build?.

Would Glyptal adhere just fine if I did the torch and paint thinner method? Can the outside of the block accept Glyptal?