l1tech is right - it's difficult to determine whether you are venting or actually want assistance. You ask if anyone has replaced an oil pump and how difficult it was and then, when questioned, state that you don't really know that it is the oil pump. The water pump was replaced, but didn't seem to fix the problem. Then, the valves are "blown", but maybe not ("pretty sure").
If assistance is what is wanted, your separate posts, each describing a defined problem, should be in one post describing symptoms. This way, the community can come together, ask questions and provide insight and possible diagnostic paths. You have to help us help you.
There were suggestions (oil pressure and compression tests) to your previous post ("My ST is slowly dying engine help needed"), but no feedback from you. Were either of these done? How much of those problems are related to your current woes?
Tapping (or sawing) noises may come from a variety of sources (rod bearing, main bearing, cam, lifter, valve, rocker, timing chain (et al), etc.).
Of course, you may throw your wallet at the truck until you have a new one, but, if you have "that kind" of money, maybe invest in a reputable shop. You'll probably end-up spending less, with less frustration and more time on your hands.
