What do all the stamps on my 360 mean?

I want to verify a few things about my 360 engine and I don't know where to start.... Can someone tell me what each symbol means? For example there is a clock looking symbol on the engine block pointing to what looks like 3 O'clock. On both sides of the block there are series of numbers which I don't know what they stand for. Also there are the letter M stamped on my heads. Any help guys. I'm sure this is really simple stuff, but I just don't know where to find accurate information on this. Thanks guys!:blob::sign3: