Timing a "unknown camed" engine....

I changed the jets...went up to 98 and used 1966 rods... now I can dial in the idle mixture much better..screws are 2 1/2 turns out now... before I had to turn them ou 3.5 to 4 turns ..
Also the rods are easier to tune.. before I had to "ilft " the TREE about 4-5 turns...now I am in the 1 turn range..

Looks like the carb was runing too lean ...right ?
Then I changed the springs in the Distributor.... Idle 18 deg...and 16 deg
of advance..all in @ 3600 rpm...
runs o.k. the AFR is 13.8 @ idle 14.4
while cruisin and 11.5 -11.8 when I accelerate hard... but there is still a slight ping...when I reach about 3500 rpm... ( I think I need to reduce the advance... )
The Vacuum canister .....that is the biggest problem... when I drive steady 55 mph the foot more or less off the gaspedal... I hear some strage sounds
comming from the engine...like pinging
If I go off the pedal the sound goes away... same if I step in harder...

Greetings Juergen