Events like the silver state classic?

I'm looking to learn about Events like Silver State Classic and the rules for the classes.

The rules and entry information are on their website :
http://www.sscc.us/

Big Bend, runs from Ft Stockton to the metropolis of Sanderson, TX:
http://www.bborr.com/

Sorry for the late reply, I just saw the post...
I have been running the SSCC events since 2013 in my 67 Impala SS. I run the 125 mph class, its not often when you can drive down a two lane highway at 125+ for 90 miles. Three days of pre race festivities with a bunch of like minded people equals a great weekend!

Resurrecting an old link.

Sandhills Open Road Challenge. http://www.sorcrace.com/. There is a link to the rules.

They have two timed races, SORC and Loup 2 Loup. SORC runs Saturday. Loup 2 Loup on Thursday. Friday is the mile (or 1/2 mile for rookies or those who prefer) shootout. All the events are on 2 lane country roads. They are much more technical and thus slower than the Silver State or Big Bend open road races.