What is the best way to ID a specific FE motor size. I have a situation, I have a chance to buy a 72 F-250 that has a good running FE block in it. On the drivers side front of the block is stamped 352. However, the old man that is selling it swears that it is a 390 and says that Ford used original 352 blocks and brought them up to 390 specs. Has anybody else ever heard of this? I want to stick this in my 67 Fastback and if it is indeed a 390 it will be a slam dunk purchase. I appreciate the help.