71 dart 17 inch streeter wheels myb need longer studs

I've seen 8 to 8.5 threads of engagement as minimum for 7/16-20 threads. I've found lug nuts go another turn or two when seating them all from hand snug. I would install a wheel, all 5 lugs torqued then remove one and count the turns to tight to be sure.

https://www.tirerack.com/tires/tiretech/techpage.jsp?techid=39&