I took the valve cover off and noticed the pushrods were able to move around more than I would think they should on #6. They moved side to side more than just spinning. I've asked around and I was told it may be that the valve stems may have been ground such that they are out of specs. The motor idles well enough but It does not gain speed and power properly. Bucks a little now and then.

Someone suggested that I needed to remove some of the deck under each rocker studs to lower the studs.
I was told by another to add washers under the nuts on the rockers. I'm going to take the valve cover off again and try placing various thickness washers under each nut on the two #6 rockers to see if I get what would look like the proper pre-load.

 

The ticking was silenced when I placed the washer under the nut on the #4 intake rocker. It would go silent but the idle was really bad with the nut tightened and kept throwing misfire codes. I tried adjusting it but there was no middle ground between the tick and the bad idle.

Just to state again this is a 1999 I rebuilt. Original cam. Pistons and rods all original but one. New bearings all around. I have tried two older sets of lifters and one complete set of new lifters and the ticking is still there.

 

While under the load of driving, this tick develops a deeper tone. The problem is on the passenger side for certain. I decided to pull the plug wires off one at a time and drive down the road a bit. The noise is not as loud when the #4 wire is off. I could not hear this until the motor was under a load. When I tore this motor down and inspected the pistons & rods the #3 wrist was worn and I could see and hear the that this was needing to be replaced. When building it back up I only replaced the #3 piston and rod.

It is my understanding that if the knocking sounds like a single knock it is a bearing. If it is a double knock it is a wrist pin.