Lifter noise

pull the stuff and check before any damage propagates into the motor

One of my cams was a Crane, the other a Comp Cams.

The failures were limited to flat tappet cams. Ain't heard of any roller failures. The two failures I had were really due to the lifter not getting rotated by the cam lobe. That was due to one of these two scenarios: poorly machined lifter face (the proper lobe face on the lifter bottom is slightly convex) Too much or too slick or thick of a lube between the lobe and lifter, thereby not allowing the lobe to get enough traction to spin the lifter in it's bore Tthe Crane failure was at initial startup in low 30*F weather. With the Comp cam failure, I litterally slathered the cam and lifters with moly lube. With both replacements, I only applied a thin film of lube on the lobe and lifter bottom to protect each at startup. I used motor oil only on the lifter sides and bores. I also verified the lifters spun freely in their bores when each was dropped in place. Both these failures happened in the first 20 minutes of run time. A retrofit roller is expensive, but then again, so are cam failures. Just me, but with a SBF, I just start with a roller block and avoid the extra expense

Do you mean with a dial indicator on the rocker arm?
How will you measure 'at the push rod'?

The only reason you should have to change any lifters is if they are wiped, and if the lifters are wiped, so are the lobes on the camshaft....

you will be able to tell if its wiped by looking at the lifter

If you are going to pull the lifters out any way, or try and ajust them again, I'd just look on the bottom of them. It will be easy to see if they have failed or not...