de-code this block

I recently purchased a 360 froma guy I work with. Its supposed to be a 72' block, at least he said he THOUGHT it was. Its a standard bord 360 with J heads so im thinking of keeping it as a spair for the duster. If you guys could just tell me what year it is, that would be great. I think you can get it from the stamp on the side of the block. Here it is. 3418496-5-360.

Any help is appreciated!8)
Author: admin