mine has just done this found my radiator was cracked and leaking causing coolant to boil at normal temp and force its way out through the rad cap. check all you pipes and radiator first then start replacing stuff cheapest first rad cap thermostat etc
Had a look at HiSpec and they wont fit my bells didn't realy want to buy new bells. My rotors are 286x25 with pcd 165mm 8 bolt. Wallace did you buy your Wilwoods from TMD. Which bells did you buy to fit Hispec Rotors?