I suggest you to take following with a grain of salt:
A friend of mine who is working in industry has learned that Intel will be preventing Lynnfield overclocking capabilities. First of all Intel will remove 4 pins from LGA1160 socket and it will be called LGA1156.
Second Lynnfield will only support BCLK (Base clock) 100 and 133 MHz, and no external clock signal fun like with X58 chipset. He is afraid Lynnfield won't be good for overclocking...
Lets hope our own DrWho? will give us some early hints and hopefully he will give me a lecture just like IDF earlier this year
(From The Overclocker issue 2)