[Ironangel]

Heating those bolt heads will do nothing more than anneal their temper,(softening the steel) thus making them more susceptible to twisting off...Heating the head will expand the cast iron around the bolt thus momentarily reliving some of the grip and allowing the Kroil to work it's magic. Hitting the bolt head into the head will help crack it loose and allow the Kroil to creep...If you have an infra-red temp gun it can come in handy, heres how. This how "I" would do it...Drain the coolant, get your hammer and extraction tools ready with a pair of gloves...Fire that motor up with no coolant in the heads and monitor the heat with the infra-red...When you read 250 degrees adjacent to a plug, shut the motor down and go to work...If that dont work the first time, soak em down, let the heads cool, wrap/hit the bolts and do it again. They will come out, just have to be smarter than that bolt!