I was changing my hg on my 98 ls and when i put the head bolts to tighten them 3 of my bolts feel like there stripped but i took my head off and i can tighten all the bolts on the block without the head idk whats the problem...do i have stripped threads on block maybe i got dirty threads any help will be appreciated thanks..

 

they could be stripped yet still thread all the way down. because there's nothing between the block and the shoulder of the bolt, the bolt will not stretch/clamp. no apposing force against it

 

The Dowels could be fudged up, throwing everything off when the head is kn

 

just blow the holes out and look down there with a flash light.
who knows. maybe that's why the gasket was leaking. maybe the last guy gorilla armed them.