""The ping starts when I am running around 75mph in 3rd and have to increase the throttle a tad to go up hill or pick up speed a little more.""

Your running Champion RC12YC plugs,high pump octane (93), 9.2 compression, no vac advance, timing at 3500, orange pump cam/031 squirter, 78 primary jets, and you still have pinging at light accel at 2700rpms and 15hg vacuum. HMMMMMM.
This problem may get worse as the outside temps go up, unless you are lean. I still suggest that you try the 035 or 040 squirter.
My second thought is that the plugs are tooooo hot in the range.
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What heat range Champion spark plugs are other members running on the street? Are 12's too hot?