After replacing all lifters, push rods, and rocker assembly, engine still ticks near #3 cyl.

SOURCE: How to replace lifters on a 360 V8 engine?

I find it hard to believe that it runs fine but, to replace either, you need to remove the intake manifold. Likely you will find both items in the lifter galley. Before dropping a lifter in there, make sure the cam lobe is still good....If the old lifter is severely worn on the cam end, likely it's not. After replacing the parts, but before replacing the valve cover and manifold, turn the engine by hand and make sure that the valve opens and rocker travel is the same as all others.
The r&r is covered in haynes and chilton manuals. One tip is to always use washers on any bolt that attaches the manifold to the heads to spread the torque load and yes, always torque any aluminum manifold to prevent warpage..
If either part has fallen into the oil pan (unlikely) it actually can stay there forever without harming anything.

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