When do you need long wheel studs

Far as I understand it Pete, you just need an open ended lugnut with a certain amount of threads showing to stay Legal for NHRA. How many threads you need showing, I'm not sure. I was told by a tech inspector, "To Lose" the Chromed ones I have, replace em with open ends n I'd "Be Fine"... With that I'll Say show 3 to 5 threads?