block heater installation

i have a 1995 tacoma with a 2.7L inline 4cyl and i need to install a block heater. i have one that i purchased from the dealer that installs into the frost plug. the instructions say to install the heater into the front left frost plug hole. i have a chilton manual but the location of the frost plugs aren't illustrated. i think i know where they are, but i wanted to make sure that i'm looking at the right thing before i knock a hole in my engine block. thanks alfred klek