Here are the cars and trucks from the movie. The unknown car may be from New Zealand because it was filmed in two locations there and in Canada.

John Deere 7700 **

Chevrolet C-10 *

Volkswagen 1303 Cabriolet [type 1] **

Chevrolet Suburban *

Pontiac Firebird *

1992-1996 Pontiac Grand Am **

Buick Roadmaster Estate Wagon *

1987-1991 Ford Bronco ****

Unknown *

Ford Ranchero *

1979 Pontiac Firebird **

Gmc Sierra *

1995-1996 Chevrolet Caprice *

Volvo 240 **

Freightliner Unknown ***

1991-1996 Buick Park Avenue *

1991-1994 Ford Explorer *

Chevrolet G-20 *

the only one i didn't inlcude was the GMC Sierra..too background

http://www.imcdb.org/movie_281617-Atomic-Twister.html