Isopropyl alcohol. 
The Tower is an excellent heatsink, I know someone else with a Prescott core with the tower112 and two 92mm fans cross ventilated it, his load temperatures rarely reach high 40s.
You may want to consider modding extra support for it though, it's a very, very, very heavy heatsink.
That's a good overclock on stock HSF though, and Prescotts are designed to run in the 60s so you should be fine with a good aftermarket heatsink.
The Tower is an excellent heatsink, I know someone else with a Prescott core with the tower112 and two 92mm fans cross ventilated it, his load temperatures rarely reach high 40s.
You may want to consider modding extra support for it though, it's a very, very, very heavy heatsink.
That's a good overclock on stock HSF though, and Prescotts are designed to run in the 60s so you should be fine with a good aftermarket heatsink.
