I noticed that right above the typical 352 casting on my block there is a "27". I thought that year of production was cast in that location.

 

Date code is below the oil filter adapter pad. Number-letter-number(s) format. The 27 you see is part of the mold numbering system the foundry used (Dearborn in this case). There is a stamped assembly date on production blocks. It's on the left ear of the block by the front of the head. Depending on the year of the block there might be a partail vin number as well. Looking at the back of the block it's on the left (driver) side, you'll see a small rectangle shaped pad by the deck. It would be stamped there. Being some vins were stamped on the head ( and some not at all) it's kinda hit or miss.