What JohnZ had to say on 6 Dec 2014 in response to a question about CE engines from ZLP is included below, and the posting is here (
http://www.camaros.org/forum/index.php?topic=12873.msg109044#msg109044)
John Z wrote:1. I had a copy of the service order when my Z engine was replaced with a "CE" short block (plus one new 186 cylinder head) in June, 1970, but it's filed away.
2. I doubt if any dealers made any effort to stamp anything on the pad - they made their money by getting the job done below flat rate and getting the car out the door; stamping "numbers" in those days would have seemed pointless.
3. "CE" short blocks were built based on demand, normally on weekend overtime; without intake and exhaust manifolds and cylinder heads, they had to be manhandled off the end of the engine plant assembly line with hoists and forklifts and placed on wooden pallets which later became shipping crates.
"CE" engines weren't "stocked" at regional parts depots - dealer order for an engine went to GMSPO (GM Service Parts Operations), who sent it to Flint V-8 (or Tonawanda, depending on the engine), and the engine plant shipped the engine direct to the dealership. "CE" engines were only supplied as short blocks or "fitted blocks" - not as "long blocks".
Based on this information, GM installed CE engines should always be dated AFTER the car they went into under warranty.