Con rod ID

The # 3418645 rod is/was used in the following:

1970-1984 360.
Late 1970-'73 340.
1973-@ '85. (Non bushed)

No bushed '645 rods were installed in truck applications, though the lighter pre-'73 318 ('782 forging) was bushed and used in car and truck apps, alike.

As far as part numbers being applicable by their year inception, crude, but, in some cases close.
1970, however, is an extreme exception. You'll find 1970 parts with a 2998*** through 351**** part or casting number.
On the other side, a lot of 1967 part numbers start with a 280**** prefix.

400**** is generally indicative of a '75 part number, but this is not the rule, either.

It's kinda' like Ford's numbering system, where C9AZ is indicative of a '69 Part number, (C=1960 decade, 9=9th year, '69) but also carries to '70.

Mark.