My son bought some parts and among them was a set of headers. They look like they are to a big block (OUCH!)Chevy! They have a stamped number on each header (same # on both , either 068 or 890 depending on how you look at them.)Does anyone out there know what header maker stamps their headers with a number and what these would fit? They were in with a bunch of Mustang parts but i know they are not Ford. Any help would be greatly welcomed. Thanks!