well I had bought the o ring kit and studs with the acorn nuts kit that goes with this head but when I took off head I found that all head studs were not straight or bolted in all the way. So I took off the studs and found the middle two stripped and the rest where a mess I guess who ever had this bike before re threaded the holes but did a messed up job doing it some studs weren't even straight. I tried fixing the holes by helicoiling them but the holes where just to messed up to fix so i just ordered new jugs instead.