Evans waterless coolant

Adjust the metering rods to rise out of the jets earlier is one way but, I would check your float level first!

Good idea. I didn't adjust the float level because I don't have a "book" measurement for what it should be. Apparently most BBD's used 1/4" but there were some that used 9/32", 5/16", or 11/32". This one isn't tagged with a casting number so I'm shooting in the dark.

I am not familiar with a BBD?
That super lean mixture is most likely adding to your pinging issue. You need to correct this first.

Something is not adding up.
Your initial timing is 9* your mechanical advance is 20*
Thus 9*+20*=29* Total timing
You need to have the distributor set up on a distributor machine. Guessing at which springs to use is dicey at best.

The initial timing is 9 degrees. The max advance is 21 for a total of 30 at 3200 RPM.

The Carter BBD was one of the 2-barrel carburetors used on the "Super Six" slant six F-bodies. Instead of a power enrichment valve, it has a pair of metering rods that stick into the "jets" (probably not the right word). The rods are tapered, and they move up and down according to manifold vacuum and throttle position to effectively adjust the jet size for different driving conditions. There's a screw on top that lets you adjust the baseline height of the rods.