1973 360 block thickness?

Way to go Scott! Come to think of it at the '10 Moparfest I remember an oldtime Mopar guru on stage answering questions from the crowd and one of the questions was the same as yours. I cant remember the exact years, but he said if you flip the blocks upside down, there is a noticeable difference. The old timer is Herb Mccandless....google his name