look at the numbers again, sometimes they look like other numbers or letters. There should be two sets of numbers stamped on the pad. One is the Engine ID Code, and the other is the VIN code. If it is a factory installed motor. If it has only one set of numbers then it is more than likely a replacement motor.

This is from one of the sites

"Note: CODE CE was used from 1968 to current year. It represents any CID and is used to indicate a Warranty Engine.
VF292800 - is an example of a over the counter crate engine. "2800" is the last 4 digits of the GM part # for the crate engine assembly. The final digit could be a year code.
Another example: A Targetmaster engine (p/n 14009800) built in 1985 could have a code stamped as follows:
A0198005 (A = January, 01, 9800 = pn, 5 = 1985)."