When I first put the hooker headers on that were sent w/FF5 kit it took me nearly an hour to get those hex head bolts on, as tightly as I could. As most of you are aware, you can't get a socket or a box wrench on them so it's just do your best w/an open end wrench. Well I had the exhaust leak. So my solution was a trip to Fastenal and bought a bag of allen head bolts. I could get at the bolts easier and was able to tighten them to where there is no more leak. HTH someone.