I attended the Mecum Kissimmee auction last year and when several cars sold from the Don Fezzell collection. "Old Reliable IV" set the bar at a hammer price of $525K (not including fees). There were a few others that sold last year as well, but not near this range.
I'd venture a guess this Aqua one will hammer in the $350K (+/- 10%) range. I'm not sure where Mecum gets their ranges, but noticed they have $375-450K.
Won't make it down this year, but I'll bet this car is even better looking in person. I've found that pics (no matter the quality) don't do these cars justice when you see them in person.