440 Timing Help

Having issues with 440 timing in a 67 coronet. It was pinging awful so I tried a few things and now it's not pinging but a bit sluggish and rough idle. Also running hotter. I have 10degrees initial and 28 advance. When I retarded the initial from 15 to 10 it was bad but then I added 10 degrees of advance by changing the stop on MSD dizzy to red. 28 degrees which gives me a total of 38. I am running 1 heavy silver spring and 1 light silver. Would like to get it idling smooth and pulling hard without the Ping. Yes I'm running high octane gas.
Here are engine specs
10:5 to 1 Hemi purple street cam 906 heads mild port 2500 stall