Brief background: My brother recently picked up a '67 Dart 383 GTS, missing the engine and trans. My father just recently recovered his bought-new '71 Duster 340, but the original engine/transmission is long since gone, with a 360 in it's place. On either car, it's been decided that finding the original numbers-matched block would be great, but highly unlikely, and it's not going to be something that's going to hold up getting the appropriate model engine in either of them. That being said - is there a specific era of block for either of these that we should be looking for? I've been keeping my eye open and trying to help both of them find a suitable engine/trans, and seem to remember reading somewhere that a certain year range was required for both of these - though, for the life of me, I can't find that reference. Supposedly, a newer 383 wouldn't fit the Dart, but I don't know if that also held to the Duster and a 340. Is this even remotely accurate, or will any 383 or 340 fit their respective cars?