Does this smell like a distributor/spark problem and not a SPICA issue of some sort?
Yes, if only because the ignition was the last thing you changed - it would be quite a coincidence to have the Spica start acting up right after a new distributor was installed. Did you have conventional points before?
I like the bad sparkplug wires theory. If your wires are old, the hotter spark of the electronic ignition may have killed them. I also like the defective coil theory. Question: Is a Bosch blue coil compatible with the Centerline ID405 distributor? If not, that may be what has killed it.
Could it be that I timed the distributor at the idle "P" mark rather than at the 5000 RPM "M" mark?
It is better to time to the "M" mark - maximum advance is more critical than idle advance. But sub-optimal timing wouldn't cause a sudden loss of power at 3,200 rpm.
Originally Posted by 61SS
If you still have the original coil and distributor you could revert to those and see what happens.
I would begin by replacing the plug wires (assuming they are old). This is good preventative maintenance, especially when converting to a hotter ignition. If that doesn't solve it, I would do what 61SS advises, and swap back to the old distributor and coil. If that doesn't solve it, then maybe it is a Spica issue.