It is still a G41.
I have a couple of C2D's (E6500 and E7500, both 2.93 GHz) with 266 MHz FSB's. One of my G41's will run at 352 GHz. That is 3.87 GHz. But even if your board will not run much past the stock 333 MHz, that is still 3.66 GHz.
You can also use one of the E3400's. Those have a 200 MHz FSB, so you will be limited by the CPU core speed and they are less than $50 from newegg.
My favorite of what is available right now would be the E6600 (3.06 GHz); about $70. That would give you a minimum overclock of 3.8 GHz.