Mystery 318 wants 30* initial timing?? Pinging hard

Well then your T-port sync has got to be off.Or the float level is too low, or the gas is sick.Or the carb is sick.
There is no good reason for your carb to be that messed up.Your teener appears to be very nearly stock.

Pour about a pint of that gas into a glass jam-jar.If it is any other color except clear to very very light yellow; it is "no good."If it is red it is waaaaay past it's "best before" date.Orange is only good for a 1984 Hyundai-Pony ( they burn almost anything).Dark yellow will burn in your Briggs lawn-mower, if you can get it started.
Spill about a teaspoon of it on a concrete surface, out of the wind. Take a piece of paper and light it on fire. Drop it onto the patch.
When it lights; if it produces a smokey flame and the flame dances up and down, nearly going out as the flame goes down, then that gas is "no good".If it goes out and you can still see a wet patch on the floor;it is "no good."

It may not be scientific, but this test has saved me hundreds of hours of diagnostic time, and saved customers thousands of dollars.Customers always say "I just put that gas in there;it's fresh". Well it might be fresh outta the jug that's been in your garage all winter! But If it's got color, it is "no good" for a carb equipped engine.

So what color is your gas?