I think $5500 is a good ballpark for that orange Fury, it's a modified car and would take a LOT of money to take it beyond a home-made-looking custom car that is not completed. Modified cars like this pretty much require you to follow the path the previous person(s) was on.
For C-bodies, they either have to be stock and very nice, or high-dollar modified to get big $$ (and even then the modified cars won't recover the investment).
Issues I see that IMO keep it's value down.
painted bumpers and front grille
trim removed (some may like that)
C-pillar and roofline trim removed (yuk!)
is not an original 4-speed car
413 not a desirable engine for building a car like this, unless this one has really fresh/good ring seal and decent CR (meaning, not a rebuild with the old 8:1 parts-store pistons)
traction bars are removable, but further the 'home-made' look
doorpanels were recovered, over top of water-warped hardboards, and attached with buttons/screws along the bottom edge
Now with all that said, it's one color, shiny and straight, and if it runs as well as it looks, it would be a fun toy to beat on without worry about abusing an original car.