How do you know any of your parts are overheating? What are you using to determine this?
if your DRAM timing is set to auto, the bios may not report accurately and will just show whatever the last manual settings were. Use CPU-z id or such to check the actual speed of the ram and its timings.
Make sure the command rate is set to 2t if you want it to overclock to 1066mhz, its a sizeable jump.
Oh, forgot to mention that you will want to check into the SPD timings. When I have attempted similar things in the past, I used other brands of 1066mhz ram as a guide to what the "standard issue" timings of a DDR21066mhz chip would be.