There are estimates claiming over 1300 hi po COPO engines were code stamped but I don't believe you can estimate hi po COPO cars based on Tonawanda engine production. Chevy production estimating process was geared to build 100,000 or more units not to build low volume COPO cars so the numbers for COPO engines VS cars may not be accurate. There were situations where engines were assembled and stamped with a code for a car that was never built. If you use engine production to estimate that particular cars production number you would be 100% off. Another example is the 1969 ZL1 Corvette where over 100 engines were built and code stamped and only 2 cars were sold to the public.
According to Chevy service documentation there were 700 hi po COPO cars "in process" on July 7, 1969 including ZL1's, Yenkos, 427 Camaros and 427 Chevelles. This could mean that there were roughly only 500 427 Camaros and 200 427 Chevelles ordered as of July 1969. July is late for 1969 Chevelle build date. The 1969 Camaro ran later but I don't believe many 427 Camaros have been found with Aug or later build dates.
*on engine codes*
I have seen 1969 engines with the code stamped on the deck with no vin number on them. Here is an interesting receipt from Nickey dated 1971 where someone purchased what is labeled a 427 "ZLX". Some dealers were selling engines called ZLX that I believe was a ZL1 spec. cast iron engine. It looks like the code is T079ID and part number was 3935494? I did find a code ID engine which is listed as a passenger 1968 L72.
http://www.geocities.com/gearhead_mex/NICKEY.jpg
[Edited by JoeC (01-14-2002 at 07:47 AM).]