Regarding your valve noise. Check the valve actuating end of the rocker arms for wear. I have seen many with groves in the pads from wearing on the valve stem. If there is wear your lash measurement will not give you the actual lash clearance.
That type of spark plug cleaner was all the rage about 20 years ago. The problem with them is that they tend to round off the sharp edges on the electrodes that the plug designers work so hard to design. Arcs like to jump from sharp edges. That's why the iridium plugs have a serrated tip and a...
Do you have the correct radiator cap. Overflow tank require a cap with a check valve such that the coolant can move between the radiator and the overflow tank.
#1 More than just pitting in that race. IMHO replace it or you will have chatter.
#2 May be OK, not ideal but OK. The pitting is not on a bearing surface.
#3 Replace the shifting fork. These forks are heat treated on the wear surface (scored surface) and that has been compromised.
If the valve lash was loose when you adjusted them then your cam/lifter interface is wearing. This is a problem that can result from the low zinc and phosphorus content in most current engine oils. I had this symptom about 10 years back. The valve lash started changing (always loose) and the...
The pipe thread taps I have in the US have "NPT" on them identifying them as 'National Pipe Thread' and they are noticeably tapered. Not sure about other countries.
Those two bolts hold an alignment block for the distributor and the oil pump which was line bored at the factory. I would not recommend removing both at the same time.