Did some checking and if what I found is correct then Terry Fair of Vorshlag raced there during a NASA Time Trial with his red TT3 Mustang and ran a 1:41.544 on Jan 13 2015. The GT350 is a beast if you got close to that given the circumstances!
http://www.nasa-tt.com/Texas_Track_Records
If you can't do it online don't wait to do it by mail:
To reserve raffle tickets by phone, call 1-800-243-5767 between 8 am-8 pm (EST) Monday-Friday.
For calls outside the USA, please call 1-248-234-7005.