Numbers on top of the piston?????

[mmaadx1]

What do these numbers mean and where can I research them 14175-030 pistons are in a olds 350 rocket. block casting #s say its a 77-79 olds 350 im just plan lost

 

[Doober]

The 030 I'm only going to guess it could mean .030" over, 14175 could be the part #.