Exhaust Manifold Casting # ?

Are there any other resources for exhaust manifold casting #s, besides MyMopar.com. They do not show the casting # that I have. It is 2863553. I have done a search on here and came up with some conflicting answers, so I am trying to find out what it is off of and what years. The other manifold in the pair is a 3418623 which MyMopar.com says is off of a 71-73 dart. They are supposed to be off of a 71 340 Demon, but I just want to verify. Thanks Warren