boiling problem

[the rig]

I have a 95 D1 with a 3.9, after a bought 30-45 min. after running at idle, or driving it seems to boil over into the overflow jug for the rad. and squirts fluid out. was told it could be anything from a head gas to heater core to a cracked plenum. if it is the head gas. is it a threat of striping the block when taking bolts out? and is the felpro gas. set sutable, or should I spend the buck and go with the factory set???


All and/or any help will be great..

[ihscouts]

Are you sure it's not the overflow tank? They split at the seam. If it's coming from the cap then it could be the cap too. I hope it's one of those and not a steam engine....