For anyone who's rounded off a head bolt trying to remove it, here's what I did:

All of the bolts from the Driver's side head came out fine, but for some reason, I had a really tough time on the Passenger's side. I ended up rounding off FIVE of 'em! One would be a big pain in the ***, but FIVE? In a fit of desparation I rushed to Sears and got the 5 piece "Bolt Out" set that I'd seen on TV, not thinking that it would do any good. After all, this wasn't a stuck nut on little Amy's bicycle, it was a head bolt torqued to about, oh, 2,000 lbs or so (it seemed). Well, I was right. I took the #7 and put it on the bolt just like they show in the commercial and it just spun around, too small to get a good hold. I tried the next size up, #9 and it was too big. Devastation! Only then did I check CamaroZ28.com, read some of the comments, and discovered that the 13mm Head Bolts require a #8 Bolt Out that doesn't come in the 5 piece kit, and that it needs to be HAMMERED on. So, back I go to Sears, buy the 13 piece set, and this time hammered the #8 onto the first head bolt, stuck my breaker bar on it and CREEEEEK! Out it came! About 20 minutes later, I had all 5 out.

From reading several posts on this topic from people as panicked as I was, I've seen lots of ideas, from welding new nuts onto the bolt heads, to cutting the heads off completely. DON'T BOTHER! This turned out to be extremely easy.

Just remember, it's the #8 Bolt Out, and hammer it on really good. You'll have no more problems!

 

Were you originally using a 6 point socket? I have never rounded a bolt head with one. I consider it a must for any bolt with much torque.

 

It also depends on the quality of the tool. Cheap taiwan or chinese sockets might not be EXACTLY the right size (they seem to run slightly on the large side if/when they deviate at all). I also second the comment about 6 point sockets. The only way I could see rounding off a hex head with a 6 point socket is if it's either the wrong size or you didn't have the socket completely or squarely on the bolt head.

 

Probably a combination of cheap tools (it was a 6 point socket) and the socket not being completely on straight. The Passenger side is a little more difficult as your pulling toward the centerline of the engine, whereas, with the drivers side bolts, you're pulling toward your standing position alongside the car. Had no problems with the D side bolts. No matter, all's well now.