Yhe number will be the same as the vin# that is on the dash and title. I think it may be located on the back of the block on a flat spot behind the intake manifold right in front(and above) of the transmission bell housing.I believe the transmission will also have a vin# stamped on it also.othe numbers to look for on the engine would be located above the starter (have to remove it to see them)those would be the casting dates of the block.
Look at the block- drivers side rear just below where the head bolts one. The original block (should check the trans also) will have a shortened version of the VIN not the whole VIN. Basically the year, production plant for the car, and the sequential number