i have the kms kit, are they hardened?
my build is near 70 also. in fact, someone just made 70 with it on pump gas...
i bought the studs for security too, but if the studs did not cause this, then what did? it was installed on clean, flat surfaces. i know the head was good, and the cylinder had only been exposed this one time since new and it was clean. im finishing the disassembly tonight, it made me too pissed last night.