After reading all the posts, my suggestion is to check the voltage with the engine at various RPMs. This is due to pulley ratio.
Around idle (800 rpm) it may only be 12 volts, but checking at 1500 and 2000 rpm should show 13.5-14.4 at the alternator terminal.

Then at the rpm the alternator is putting out 14 volts, check the voltage at other places, battery terminals, MSD or accessory points.

1993 Daytona, 5.50 at 130mph (1/8) 1.19 sixty ft (PG). Link to 572 B1 - Part 1