Dear PM;
I would replace #6 exhaust with a new pushrod and rocker arm.
While your at the dealer see if they make adjustable or 'oversize' pushrods for that engine.
The lifter bore is not likely as the wear occurs on the valve stem, rocker/pushrod etc. I have seen the stud(s)that hold the rocker (fulcrum) pull out enough to cause this however on various engines.
I wouldn't worry about the rest, as the .005 will "zero out" when hot.
Good luck, JM, #3370
