Threads stripping out of aluminum head

[oklahoma]

Hey Guys. Got an issue I've never run into before here.

1996 Cutlass Ciera 3.1 with newer style heads and intake manifolds from 2002 Grand Am 3.4 installed 2011.

Car developed an external intake manifold coolant leak so I took it down to do the LIM gaskets.

Putting it back together, I had:
-One intake manifold to head bolt strip out of the rear head upon torquing
-One rocker arm assembly bolt strip out of the rear head upon torquing

Any hints as to why this head has apparently gone soft and keeps rejecting bolts? Any reason to believe that another head pulled from the junkyard would behave the same way?

Again head is aluminum 3.1/3.4 pulled from 2002 Grand Am in 2011.

Trying to decide whether to try a new head or have the junkyard haul this old thing away. Old car's about used up anyways and I got plenty of other ones.

Thanks
Jack

[TazMan]

Both have happened to me a few times. With the manifold bolts I was able to get a slightly longer bolt to torque down good without stripping out. If you CAN go that route make sure it's not too long. You can helicoil the rocker arms and they should hold up without a problem. I've had to do a few and they always feel stronger than stock to me.

[Guest]

I had that happen once, due to putting the wrong length pushrod in the wrong spot. :/

Just heli-coil the holes and continue on.

[TazMan]

I forgot to mention, I had a bad torque wrench screw me up good once. It wasn't till two helicoils later i got suspicious and checked the wrench to find out it was bad so if there's any chance of that, check or replace that wrench b4 you move forward.