You fail to mention what body style it is. If it is a 2-door (coupe or hardtop), now we're talkin'. If it is a 4-door, it is just another old car . . . albeit one with low mileage.
There were two desirable engines available for this car:
Sprint
350HO
As u say yours is a 350, is it a 2bbl. or 4bbl.? The latter means it is an HO, which r rare (about 3000 built in all Tempest/Lemans models, I believe) & put out about 320 hp. More desirable is a stick shift, but automatics were available as well. Is this what u have? Then certainly ur car could be worth what u mention. Otherwise, I think you're being optimistic.
Assuming it is the more popular, lower performance 350 with the 2bbl. carb, & assuming it is a 2-door, ur best bet is to sell it as a low-mileage car & mention that it is perfect for someone to drop in a 455 or something like that - the car is perfect for someone who wants to go fast.