what are you running down the road with
what does the tach read,
40 degees.wow take the dist out and realighn the timing marks,drop dist back in
dead on.check the book.IF REQ
40 degrees sounds like your motor has
high lift and duration as well as overlap
and cam lobe degrees.
pinging is piston knock,yeah sounds
like marbles in a can ,it is caused by detonation in the cly ,there are areas on the piston that are carboned up that cause the secondary ignition/detonation/flash.
decarbonize the motor,yes higher octane
allievates the problem only cause it burns faster,less burn time.
advance the timing masks the problem .
some people mistake timing chain rattle
noise with pinging.
yes going up hill is a good test tool.
fix it the right way..................