Just posted to your query on Moravia's board.
I would say that DVOR'AK and VARAK (Vorak) are two different surname unless your ancestors were originally Dvorak.
Take a look in http://linktoyourroots.hamburg.de
DVORAK, VARAK and DLOUHY list in Moravia's region of CZ's phone book. http://phone.quick.cz
No W in Czech alphabet. The English Y makes the J sound.
Have you heard of Leo Baca's 9 volumes Bohemians to America? Your ancestors could be in there.