It is on the engine block behind the cyclinder head on the driver's side. It is burried way deep (keep looking). This is one of those stand on you head
routines :) It is stamped on the engine block. You may need to clean the engine before you can find it (use a screw driver and rag).

The easy method is to look in the service manual /owner's manual if it is still around. There is a card on the inside cover which has the engine number printed on it.