I ended up doing the exact same thing. I overtorqued one of my intake 8mm bolts and snapped it inside the head. Thank goodness it was one of the very forward bolts though because if it was a rear then you wouldn't be able to reach it without pulling the head... My bolt broke almost flush with the head so I got a reversible sided easy out at Home Depot, drilled the conical shape dead center with a power drill, reversed the bit and it pulled right out no problem. Good luck!

 

Yeah I am positive that it is an intake bolt as mentioned above. I have replaced the manifold several times so I know which bolt it was. And it is my very front bolt on the driver side of the intake. Although using any sorta EZout is out of the picture. I think my only possibility now is using a heli coil.

And the post above gives me a good idea. So with the new intake bolt, I can get the threads a few turns in before it hits the oil bolt, I wonder if I could put a stud in and then put a nut on top and tighten it down. I know this is going to be the cheap and easy way but if it secures the intake down then ok. Right now that bolt has basically no pressure on that bolt.

 

Keep at it with the ez out, you'll get it eventually.

This is a good reason to invest in a Torque wrench set. Working on old SBC motors, I'd rarely use mine save for things that had sealing issues if overtorqued. Never really found myself in a situation where I overtorqued a bolt by much.

The LSx motors scare the **** out of me with torque specs as being all aluminum the chance of stripping something is very high.

 

I wish I could try it again with the EZ out but I had used 2 sizes and I think if I tried another size up then I will end up stripping out the hole completely. I wish someone in this thread was in Houston!

So:
1) Helicoil
2) Try above method of stud with but on top to tighet it down.

 

take the intake back off.
yes the intake bolt threads into the head
it's stright up and and down, and not off to an angle
block off the intake ports with some rags or paper towels
get a center punch or a nail if you're too cheap. Use that as your center for starting the drill bit
get a kit just like this, and a cheap t-handle and not a cresent wrench. This kit are from Home Depot, Ace, or Walmart to just about any cheap tool store. It tells you what sized hole to drill for the reverse tap.



http://www.doityourself.com/invt/5089479

 

I think it's a little late for the screw extractor route at this point or at least it sounds like it from his description. This site is always more helpful when you ask your questions BEFORE you do the damage. You should have used a sleeve to guide the drill bit to the center of the broken bolt since the bolts never break of square and flat. Without a sleeve it's nearly impossible to get the drill bit centered over the broken bolt. If you drill the hole off center by trying to drill without a sleeve to guide the drill bit you're only making a bad situation worse. You should pull the head and have a machine shop install a heli-coil. If you used a screw extrator set without knowing how to use it properly chances are you won't have much success with the heli-coil either.

 

Drill it, retap it and helicoil it