E14 is the body build date, and in your case would be December 14th, 1964. The body build date normally preceeds the final assembly date by 1 1/2 to 2 1/2 days. You have a St. Louis built body as the S1485 shows. A. O. Smith built bodies for 1965's also, but they are identified by an "A" in the body number instead of an "s". The 900 was a carryover in paint numbers from previous years, and doesn't show anything in 1965 as all 1965 Corvettes had the 900 prefix in the paint code.
An excellent book on the 1963-1967's is "The Complete Corvette Restoration & Technical Guide - Vol. 2 by Noland Adams. It is $70 or so now, but is well worth the price for mid-year owners. The above info comes from there.
I liked it so well I bought the 53-62 version as well.
Rlm