Casting numbers only reflect the origin of that core.
i.e. the vehicle it was originally designed for.
351W's were likely first used in a 72 Galaxie.
Heck, my '87 truck has C8 parts in it from the factory.
Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.