If it is the original engine in your Vehicle then the serial number is also the serial portion of the Vehicle Identification number, along with selected other dights
The vin encodes the manufacturer IE FORD, the product line (chassis size.model) The plant, the year The engine and transmission and the ORIGINAL serial number which is shared by Engine, Tranny and Assembly.
IF the engine has been "Swapped out" as mine has you will may need to get someone from the police Auto Theft Devision to find it for you. THey put 'em in assorted places depending on the engine size. Used to have the book listing them at the office.. it's still there. I"m not, I retired.
Home was where I park it. but alas the.
2005 Damon Intruder 377 Alas declared a total loss
after a semi "nicked" it. Still have the radios
Kenwood TS-2000, ICOM ID-5100, ID-51A+2, ID-880 REF030C most times