The MP stamped on that block is familiar. I had two of those at one time. I did not think much about it. I traded one off for a better dated block for my 65 car. Then I read an article in one of the Mopar mags that said they were installed in 67 RO/WO cars. If my memory serves me correctly, they were both cast on 10/31/66, Halloween. I sold my last one to a board member here with a 67 WO car. I think he still has it. Joel might remember.