Fried ECM

Another tidbit - that's probably got a late 60s timing curve in it (for Clean Air Package)
If so, then it doesn't need much timing at idle. Plymouth suggested 7.5* at 650 rpm on the std perf. 440 with automatic.
If you try more inital advance, it might ping at either part throttle or full throttle once the engine is fully warmed up. If so, back it down again.
If not, you can try a little more again. But no more than 12-14* at 650 rpm should be needed on a stock engine.