but I can hear a slight "knock", "click" or "ping" coming from the motor.
I am not a mechanic at all.
You'll have to forgive me, but you're talking over my head already I have no idea what the timing is set at and wouldn't even know how to check.
Which tells me that you would not be familar with what a detonation sounds like
Check for any leaks around the exhaust manifilds, in particular the rear ports..check the bolts are tight
Check at night if there are any HT leads jumping/leaking spark
Using a long screwdriver with a solid handle (not rubber) one end on the engine the other to your ear to locate the sound...this will locate stuff like
Check lifters adjusted correctly
A lifter touching the tappet cover (thicker cork gasket fixes)
Alternater, pullys, bellhousing, cracked or collasped piston.
And also put the engine up on a hoist and check the unnder parts of the engine.
Thry the higher octane and also dropping the timing back aboutr 3 degs
Also try disconnecting the VA and block the hose.
Plan of attack:
I have owned this vehicle for 6 months and it's my first classic car.
The 1st think you should do is change the oil, flush radiator and grease
I assume that you are not familar with this
book the car into your local service station, ask that you be there when they do it
Copy this post out and give to them.
While they are doing the service you can watch and learn
They can drop the advance back, use a mechanics stethoscope (instead of the screwdriver) while up on the hoist. and check tappets.