what year 302
If you are referring to a Ford 302, turn the block upside down and next to the pan rail, on the side of the block you will find a flat spot with a 4 place letter number combination.
If it starts with a C, that indicates made in the 60's, the number next to it will indicate the year. IE C9xx, means 69, and the other two letters indicate the usage and option .
D =80's
E= 90's
Warning though, some were cast without it, so you will have to look elsewhere on the block for that letter/number combo.