and more about installation. IE: Were head bolts re-used? Did you use an aftermarket head bolt or studs (ARP) without the properly sized washers? Did you follow the proper torque procedure? Was your torque wrench of good quality and calibrated recently prior to assembly? Etc. Your profile build list says ARP - there was discussion about this a little while ago concerning the washers used not being adequate. Can't remember if this was only related to IPP's engines or if it had more to do with what ARP supplied but I remember you're supposed to use oem washers beneath the ARP washer.