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2011 chevy camaro SS auto
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OK. 2011 chevy camaro SS L99 auto.

Symptoms noticed were rough idle, shaking without check engine light, no misfiring. Noticed uneven cylinders' compression on cold, 180 - 200 psi. That is what was done.

A month ago I removed both heads, cleaned the pistons (upper side) in combustion chamber, valves. Removed valves, replaced all valves' stem seals and all springs.

Pitered the valves with special paste to fit the valve seat, and checked all valves for tightness with kerosene.

I removed and washed all lifters in purified aviation kerosene. Only one (non DOD) had several strips on the roller that could not even be hooked up with a fingernail. Replaced all lifters' guide trays. DOD lifters were found OK, springs were not collapsed.

Replaced camshaft gasket that was found in bad condition without rubber gasket. Also replaced camshaft adjuster magnet and it's sensor. Replaced spark plugs with Delco, VVT sprocket (Delco), VVT valve and timing chain (Delco) with tensioner (Delco).

Replaced harmonic balancer that I thought could be one of the reasons of rough idle.

All fuel injectors were cleaned in the detergent with USB adapter that imitates ECU / real operation on engine.

After assembly, a complete engine diagnosis was made, long-term and short-term fuel correction, the timing chaid was checked by the vacuum in the intake manifold (measurement of the vacuum in the intake manifold allows you to determine the malfunction without disassembling the engine).

Replaced oil pump (Melling) with standard oil pressure. Cold start 50 psi, hot idle 23-25 psi, cruising 35 - 50 psi depending on speed.

VLOM and oil channels were cleaned, oil pressure sensor screen cleaned and installed back. I am always using the Range OBD device so VLOM is OFF while driving.

There were no extraneous sounds .... for about a week. Replaced exhaust manifold gasket, so it's not an exhaust leak sound.

NOW, I have a
1) quiet clicking noise on hot idle, looks like coming from Cyl#7. Is it OK or I have to replace all the lifters ?
2) rough idle on cold idle and sometimes on hot (randomly). I heard a lot of people have it. Should I pay attention to it or leave it as it is?
3) when I accelerate on cold I can hear a chirring / ticking sound looks like coming from VVT side (accelerate only, sounds as "tr-tr-tr-tr-tr"). This sound goes off approx on 180F. Likewise, I've heard that many have it. Should I pay attention to it or leave it as it is?

There is a suspicion that the round heads of the Push Rods has erased and can click. Maybe this is the reason of clicking ? It is almost imperceptible to the eye. I turned them upside down and put the "erased" side on the lifter, but no change in sound...

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