Roe Racing or try it out at a ViperDays event with Archer. The HiPo Engineering vent tube allows you to quit worrying about this. It doesn't allow the cap to turn, it gives another inch that fluid would have to travel up in order to leak out which is handy for road racing, it looks OEM in nickel or you can get it in chrome, no drilling or modifying required, and less than $30.