trying to identify my engine PLEASE HELP?!

[Thomlost]

Here's an attached picture of the numbers I found on the front of my block... My main question is do I need all of the numbers to find out what year, etc. about my engine?? The bigger ones are pretty easy to figure out (V0603TYY) but the smaller ones to the left it looks like there's possibly two sets looks kinda like 5Z and 729... I'm really not sure if it's a "Z" and if there's any numbers in between the two sets that just happened to come out lighter and it's really one big alpha numeric number... if I zoom in on the picture it kinda looks like 5Z157729 but the 157 in the middle are really really light and my eyes may just be playing tricks on me... so yeah any help would be greatly appreciated!!