My machinist hot tanked all sorts of blocks. He only ever installed one. The reason I asked him is he sold me a freshly machined shortblock 340 from his personal stash. I asked him about the plug. He said leave it alone. When I bought the block from him he replaced all the cam bearings for free, so If he thought it needed changing he would have.
It's your engine tho. Goes against what 90% of people will say.