[Fixittt]

\Jim that rod that comes out the bottom of the calipers is what I use.

you are talking about a depth gauge. Your calipers would dop the same thing. I also mounted my block with the MOBO outside the case, so that I could have more access to it. After leak testing of course.

Also, you didnt crack the core, you crushed it. I have a good 2 hand fulls of chips that I have crushed without showing any signs of abuse. It just happens. "Have a keychain"

as for the shim. I dont have any personal experiance with them, nor do I know who would be the best to get. But I have heard that some lower quality shims will either (Being to tall) keep the block from touching your core, or being to short) will not protect you at all.

So keep that in mind and when you do get a shim which I think is a ver good idea. make sure you take alot of measurments before just slapping it in.