I can vouch though I found a 413 in a 67 imperial which the 413 did not come factory in a 67 imperial. The ID pad was blank but the casting number was allegedly the same as a max wedge block I cant recall the year the block was it's been 5 years but i know buyer was very happy a week after buying it and And pulling it apart for a refresh and it was a .060 413..... i dont know how or why it was in the 67 imperial but I've pulled hundreds of engines and i have no doubt it was factory install or someone swapped it in and did everthing 100% correct. not one single hose clamp was wrong or incorrect either. Really wish I would have hung onto that one. I have a found a 340 in a 72 dodge van before. Van looked 100% stock as well even the underhood decals showed it was a 318ci. Makes you really wonder how and why and if these left the factory this way.
