RV-6/6A, RV-7/7A, RV-8/8A
Hoizontal Stabilizer Cracks
All RV-3, 4, 6/6A, 7/7A, 8/8A Flying aircraft
Cracks in Elevator Spar
Both recommend grounding the aircraft until an inspection is performed. Until the reinforcements are added, this becomes an annual inspection item.
LONG discussion on Vansairforce, just search for the SB number and you'll find the threads.