How do identify what year my engine is?

Start by looking at front of block directly below head, driver side. If it's rebuilt it may be stamped out, but the OEM had a long string of numbers stamped there and I think you skip the first 1 or 2 numerals, then the CID is the next three. As said below, if that is eradicated, look down low on the block for casting numbers.

If it runs smooth and does not vibrate, it likely has the correct balancer. Look at it. If it's an obvious "off center" weighted, it's a 360.