Block heater location 3.0?

I just bought an engine heater and according to the info I am supposed to install in block behind alternator but the frostplug is just too small. Those of you with block heaters please tell me where yours is located or any other alternatives. 2001 Eclipse GT 3.0

Found the best spot at cylinder 5 right above block drain, now I just have to go back to the parts store and exchange the heater.