Wes,
The 14" Blizzaks will probably fit on your rims but will they hold the weight of your van?  Miata 2000 lb., Vanagon 4000 lb. (give or take)  Do yourself a favor and look for something with a "C" load rating.  I have Nokian all season tires on my Vanagon and on the Chevy 1/2 ton I drive for work (I didn't buy it).  I am happy with the tires on wet, dry or snowy roads.
George
'85 Westfalia