In 1965 the Corvette VIN configuration was changed from the earlier 1960-1964 format. There were now 13 characters, although the basic information remained the same as previous years, just rearranged slightly in their order. The basic information was still shown including year, body style and order in the production sequence. The 3rd digit now signified a V8 engine, but not which one. Later in 1972 the engine digit would become more informative and specify size and horsepower rating.
1965 Corvette Example VIN - 13 digits
1st digit - Make/Manufacturer: 1 = Chevrolet
2nd digit - Model: 9 = Corvette
3rd digit - Engine: 4 = V8 (all engines)
4th+5th digits - Body Style: 37 = Coupe, 67 = Convertible
6th digit - Model Year: 5 = 1965, 6 = 1966, 7 = 1967, 8 = 1968, 9 = 1969, 0 = 1970, 1 = 1971
7th digit - Assembly Plant: S = St. Louis
8th-13th digits - Production Sequence Number: Starts at 100001 with each Corvette produced being assigned the next number in sequence. Last sequence number should equal total production for that year in almost all cases.
Decoding the VIN is just the first step when looking at potential Corvettes for sale. It's also important to confirm "matching numbers" (ie. verify original equipment like engine, transmission, axles, etc. )