I purchased inserts on ebay for my original 15" steel Z28 wheels, only what I received was the wrong thing. The only thing I can think of is they must be for the optional aluminum wheels since they are nearly the size of the whole center cap. The seller works as a Mgr of a Chevy Parts Dept. and he's saying that these 2" inserts are for the standard '78-'79 Z28 wheels and I don't know what I'm talking about, and must have the wrong wheels. He's even saying the emblem design is for '78-'79 wheels, when as far as I know it's the '77 and '78 that shared the same "Z28" emblem design and '79 went on to a different one. Anyway, how could I have the wrong "steel" wheels? I know they made different revisions but the center caps are the same aren't they? Mine need about a 1.5" insert? The part number on the center cap inserts I was shipped is #00474316. Can anyone tell me if this is the part number for the insert for the optional wheels? And more importantly...what's the correct part number for the center cap "insert" for a 15" steel Z28 wheel with the '78 Z28 emblem? Thanks!