Yep, your temps confirm it, most don't want to go much over 50C-60C. Get an aftermarket CPU cooler. You don't have to spend a lot of money: newegg has the CM Hyper 212+ on sale for about $32 delivered. I think I saw the Arctic Freezer on sale, too.
I recently OC my e6750(2.66Ghz) to 3.2Ghz on Asus p5b deluxe. When I ran Prime95 for just 5 minutes, CoreTemp reported 85 degrees celcius
All I did was raise the clock to 401, set RAM to 802, raise vcore to 1.35, raise fsb to 1.4v, and everything else on auto. Is the stock HS really THAT bad?
That's way to high for the e6750. I have one too, but got zalman cnps 9700led (zalman cnps10 flex arriving tomorrow ) Currently mine is clocking at 3.52ghz and temps stay under 68C after 8hrs of prime95. At least remove the stock thermal paste off the heat sink and use artic silver 5. IMO you shouldn't need to raise the fsb voltage at those speeds.