There a couple GM guys here that used to run big, big blocks. Anytime anyone would ask they'd say a little over 500". I eventually found out that one was 599 and the other was 580 something. They both knew my old engine was a 408 so when the 434 was finished they were questioning me about it and wanted to know how big it was. I told them a little over 400". I just rounded it down. LOL