As an update, my SSP hasn't been running right this year. The car had carb issues, but a new Holley failed to fix the bad idling problem (the car would not smooth out). I decided to have the car looked at by my nephew, Kris, who owns a custom (repair) shop and is VERY familiar with 5.0L Fox Mustangs. He came by on Halloween and picked up the car on his flatbed.
So Kris checked the car out, and determined that the harmonic balancer was about to separate from the crank.
It looks as though the off-balance balancer took it's toll on the bottom-end, because the crank now has excessive play. In addition, my oil pressure at speed is only 30psi, and at idle it's around 10psi. Compression ranges from 110-160. So it looks as though the tired old 5.0L is worn out.
Since I am trying to finish up other projects, I will be having Kris yank the engine and open it up to see what's inside. Since I am the 8th owner of the car, I'm not sure if it's the original motor or not. Hopefully the block (if it's original) isn't already .030-over. If the block is shot, then I need to decide how to proceed with the engine.
In terms of the lemonade comment at the beginning, once the motor is out, I'll get the car back so I can detail the engine compartment. The under-hood area was in dire need of attention, so I'll used this unplanned event to spruce things up.