[LimaCharlie]

Here is the first Z16 (396 option) Chevelle. Notice it is a 1965.
The story on the bottom of the page says only 200 396 Chevelle's were made at the time and all were GM prototypes.
I guess it's still possible that a 396 prototype was made in 1964. If it's true and the car your dad saw was VIN 0001 for 1964, the car would probably be worth more than this VIN 0001 1965 model.
The value on cars like this is determined by how much someone is willing to pay. One thing is for sure.....6 figures...easy!
Check it out:

http://www.z16chevelle.com/First%20Z...0Prototype.htm