OH OH,, I think I know this one!!
Well, one at least, the Essex Wire Cobra? White in colour?
The 289 Coupe ran the same motor the roadster's did, so h.p. would have been the same. Aero was a HUGE difference! I understand the Gran Sport in '63 was a competitive car, but Cobra killer? I don't know about that. Also I think '63 was the first year for Vette IRS, (and disc brakes?), a major improvement. Not to mention the Aero advantage!
Ron? Cal? What say you?