I have always had a clicking in my 235. I decided to look into it. I've checked my valve lash and I'm sure it's not that, there is a very loud clacking noise when the rockers are too loose. Different than the noise I'm talking about.
With the valve cover off, I narrowed it down to a specific lifter and rocker. When I push down in the rocker, I can actually feel the difference compared to the other rockers. The movement does not feel smooth like the others
I'm thinking its a sticky lifter but I'm not sure. Any ideas, thoughts or concerns?
you might want to check the length of the bolts holding the coil to the block. Mine were long enough to protrude into the pushrod cavity and scrape against the pushrods.
FWIW: With a good video editing program that allows you to see the audio track you can zoom in (expand the time line) and isolate the 'tick' and see what position things are in. I've used the technique before when stumped as to the 'where and which one' question I wasn't able to isolate.