I am partial to the High Sierra antennas, the full size models, especially if you want to work 80m. The littles one will work, but like all antennas, on 80m bigger is better.
I have an 1800Pro on my Windstar and routinely work all up and down the Eastern coast and the deep south on the MARS frequencies adjacent to 80m from the Baltimore area.
You DO want to read Alan's web site,
www.k0bg.com. This is one of the best sites for do's and don'ts on mobile HF.
73,
Lon - W3LK
Baltimore, Maryland