Where in VA? I live in Chantilly but mine are registered at my property in Fredericksburg. Since the Pantera is an antique I dont deal with this now but in the past the valuation was all over the place. I.e., when I still had my Diablo in 2015, they valued it at like $37k lol (so assessed annual tax was about 1275 but there was 220 relief, so about 1055 a year). Diablo was worth more so I have no idea how they came up with it but sure wasn't going to complain.
When I had my 05 Gallardo in 2016, they valued it at $104k (yearly bill was about $2800 after about $200 relief) . So it was hard to tell what to expect. Try contacting meandmyredcorvette on the other forum. He has 1 or 2 6.0s and lives near me so he can probably give a better idea on how much they value them at. Hope that helps!