The tapping is the lifters.

My GTP is having a bouncing issue at certain speeds as well and I think it's the axles. Everything else up front is tight and new; hubs, control arms w/ new bushings and ball joints, tie rods, struts and mounts etc.

You would need to jack up the car and hold the tire at 9 & 3, hold the back of the wheel and push the front. See if it has play. That is to check tie rod play.

Hold the tire at 12 & 6 and pull the top then the bottom and so on, depending on amount of play its' a ball joint or hub.

If these are all tight then it's likely an axle.