yup, everyone got you covered already.
Here is a picture of where mine "was" just follow the coolant stream to the block, you will see where they are located.
One on the front (left) and one on the rear (right) of the block about in the same place either side.
*I had to drill my knock sensor out of the block because it came apart when I went to unscrew it from the block. Pretty much broke off its threaded base, leaving that behind in the block for me to have fun with.
~F~