cadillac block identification?

I have a 55 caddy that i am trying to identify the motor in (i am not sure if its stock or not), the casting number is 3970014. anybody have an idea as to what this is or where to find out? I will post a pic of the motor by the end of today. Thanks!

 

look for the engine number stamped on the block, top front right side just below the head. first two digits are model year, so if it's a 55 it will say 55xxxxxxx

thru 55 they are 331, 56-58 is 365, 59-60s 390

 

Found it, somebody stuck a 350 in it. Thanks!

 

the number in front of the head on the top of the block, passenger side, just like a Chevy V8