I picked up a rebuilt engine from a guy who stopped his project truck. The engine is a 390 4v intake with Edelbrock 1406 600cfm carb. For the ignition I have a Pertronix kit installed with factory coil. The engine was rebuilt with a performance cam but I have no idea what it is nor do I know the compression ratio.
Now my problem. I put the Duraspark 1 series distributor in but had terrible ping no matter what I did so I went back to the points distributor and put the Pertronix in.
I went ahead and picked up a rebuilt distributor. I have my choice between the 10/15 mechanical advance or the 13/18 advance. I started with the 18 and got ping. Then to 13, then 10. I've moved my initial all over the place from 6-14 and still have ping. With the 10L slot setting and initial around 8-10 has been the best so far. With this combination I could press the accelerator past the ping when the secondaries opened up. This led me to believe the carburetor needed tuning. It was already in a stage 2 setup. I ended up using the .101" metering jet with the .070"x.037" rod. This combination has the least amount of ping.
With the engine warm I can accelerate until just before secondaries open up before I get ping. Press on down even to WOT and no ping.

What do I need to do at this point to get the last of the ping out? I've tried running mid grade octane and even tossed some octane boost in but the boost didn't make any difference that I could tell.