I have made two changes that appear to have taken me
much closer to "good to go".
- I switched to premium unleaded gasoline per one of the suggestions above.
- I tested the original Bosch ignition coil and found it wanting as to the factory ohm readings. I replaced it with a new MSD Blaster 2 coil which tested out perfectly as you'd expect with a brand new part.
Those two changes made a world of difference. The car is much more enjoyable and seldom shows the flat spot acceleration I asked about originally.
I have an analog MSD 6AL ignition box I plan to install too. Other Pelicans have made that upgrade with good results. None of the threads I've read tell me how to do it other than to say it's easy. I can dig deeper to find the procedure or get help from MSD. My biggest question is what lead I use to get the trigger signal from the engine. If anyone already knows that answer, it would keep me from starting a new thread.
Thanks again for all your suggestions. They all helped me find the final solution.