There is something called Nascar Heat UI Control Center which I think you should still be able to find online somewhere to download which allows you to change the in game resolution beyond the standard ones that are shown within game. This 'might' be worth a try as the resolution options given in game are limited in todays market.
Also have you tried changing the graphics settings in game to minimum and maximum to see if the issues is the same there and also try the various resolution options in there also.
Hi
Dont know much about the game you are playing, but would try the settings like mentioned above, also found this info might help.......
http://forums.opensuse.org/english/get-tec...cy-problem.html