Your progress is remarkable.
Bill Hilscher and the Yenko Chevys from Texas comes to mind.
While we have a number of SCCA types floating around here, your question related to them should be directed to them.
On the questions related to LSR, you will find in the area of car safety features, all the Clubs strive to be close to the same.
I would expect the air handling and the provision for the drive shaft meet both the spirit and intent of the rule as built.
I would suggest you contact the Rod Riders for membership information.
WDJD