I have a 67 with a 68 WZ unknown miles, I pulled the engine 10 years ago to clean it up and check things out, winter project. I flipped it over on the engine stand and pulled the pan, this is where you'll find out how deep you need to go.
I found about a dime size of graphite like material in one corner, the piston sides looked great and the cylinder walls looked like they had been just down, this motor had never been apart, like I say I don't know the mileage.
While it was out I did the timing chain, cam to 068, lifters, oil pump, I did not pull the heads.
The ticking you describe is probably the lifters, Pontiacs are known for a lifter tick and they were probably drained of oil from sitting, if you're pulling it out of the car it's nothing to pull the valve covers and intake and pan valley and take a peak and readjust them.
