1999 Grand Am GT ticking

[mjtr21]

i still dont see how a leaky head gasket could cause that ticking. well the car used to do it but hardly if at all noticable. then all of the sudden i came to a stop light and went to take off and it started the damn ticking. maybe i will get a compression test done before i replace the engine. and with that oil pressure sending unit is that an easy job? where is it located? thanks for the suggestions.