Ford Repair: 1992 Super Coupe dead cylinders, noid light, dummy plug

Question
1992 T Bird Super Coupe 3.6 supercharged.  Previously had detonation problem that damaged 2 pistons.  Had long block rebuilt by reputable shop, reinstalled in car.  Engine started on first try but #4 & #6 do not fire.  Appears to have spark, although sometimes seems erratic when connecting a timing light to these two plug wires.  Installed new injectors on these cylinders, no help.  Replaced coil pack, no help.  Has compression.  When pulling plugs, they are clean and shiney, look like no fire at all.  Connecting plug wire to dummy plug shows spark.  Rechecked plug wire connections and they are correct.  Thank you.

Answer
Any codes?

If the plugs are clean and shiney the injectors may not be firing, otherwise the plugs would be black and sooty. The injectors are controlled by the PCM, and timed by the distributor. Use a noid light to check for power at the injectors.