Technical Odd test result while diagnosing rough running engine

Flat cam?

 

So, wild vacuum readings, high compression on a couple cylinders and 'walking the cap' caused an pretty big increase in RPM?
Vacuum leaks would cause low but even vacuum, lower compression (cylinder wash) and would not increase RPM.
Ignition would cause bumpy vacuum, lower compression and possibly a bit better RPM.

Valvetrain, no doubt. Check up top as you said, but also check the chain slop.
That alone won't cause the issue, but if you are going to tear into it to fix the valvetrain, check/fix the chain too.
Bring the engine up to TDC#1, rotating clockwise.
Slowly rotate the crank counter-clockwise until the dist. rotor starts to move. Note how many degrees it took for the movement. 0-5 great. 5-10 weak. 10 plus, sad.

 

I was hoping for a more definitive answer after pulling the valve covers, like an exhaust valve that wasn't opening, but all the valves were definitely moving. How much? Enough that it wasn't obvious that one, like cylinder 5, wasn't opening. That said, the lash was pretty loose. I went ahead and adjusted lash and preload across the board, figuring that some could easily be loose enough to prevent sufficient opening of the valves. In the process, I didn't notice that any of the pushrods felt bent as I spun them between my fingers. Should it be obvious if a pushrod is bent? I proceeded to turn the engine over to observe the valves and the rotation of the pushrods, and they are all rotating. I'm not sure if a rounded lobe would be indicated by a non-rotating pushrod, but I felt better seeing them spin. I ran out of time before I could run another cold compression test but will tackle that next.

I'm certainly not ruling out a rounded cam lobe, but my eyes couldn't really differentiate any significant difference in valve movement. I suppose it doesn't need to be significant to cause a real problem though. Thoughts? Other things to test?

Oh, and my chain slop was about 4 - 5 degrees Rod.

 

Did any valve require more adjustment than the others . Usually a used running engine wouldn’t require valve adjustment, UNLESS the cam rounded OR the adjustment not isnt locking anymore .

 

Or a stud is pulling or a rocker is eating itself or a lifter is sticking / worn internally or a valve spring is failing ........