I have a 1972 cutlass that came stock with a 350 rocket, I have a 455 in it now and don't know how to tell what motor it is, I've read that they made ones that produce different horsepower, how do I identify my motor and its detail?

 

The information on this page will help you narrow it down: http://www.442.com/oldsfaq/ofblk.htm

 

Short of disassembling the motor and measuring the cam lobes and valve sizes, you'll never know for sure as there isn't too much you can tell from the outside. The VIN derivative stamp will tell you the year of the block. The head casting codes will tell you the year of the heads. Those alone won't tell you much, as Olds put different size valves in the same head castings. Given that this is obviously not a factory installation, you don't know what was done to the motor by the P.O.