I used to run a 216 in a '52 3100. It would ping under load up a hill no matter where you set the timing. I could certainly make it happen earlier with the wrong timing.
I have a '53 235 with hydraulic lifters which I cannot make ping by adjusting the distributor.
I am going to suggest that mechanical lifter engines are going to ping under heavy load. I am not convinced that this "ping" is the dreaded detonation we are often warned about, but rather the nature of theses beasts.

Here is a quote from the Chevrolet Truck Operators Manual for 1952. (the little book what goes in the glove box.)
"Road test. For best performance and economy the the octane selector should be set to produce a slight ping upon acceleration at wide open throttle."
Carl

1952 5-window - return to "as built" condition | 1950 3100 with a 235 and a T-5 transmission