New Ignition coil, rotor, and distributor cap, but no spark. Need help.

Power to coil in run and start, check.
12 volts to blue/ylw wire in ECU harness, check
Blk/ylw wire to coil -, check
ECU has a good ground, check
Ground strap on engine, check.

I found the ballast resistor, I'll go grab a new one of these. Or is there a way to test it?

Also, i'd hate it to be the ignition box, those are expensive. But do those just die in an instant?

BTW, there is absolutely no spark. The engine doesn't even try to run.

I had the exact same thing happen to me and after exhaustive ground/wire/coil/ballast/ all the usual suspects came up a no go it ended up being the pickup in the distributor.

What ECU box are you running OEM style or MSD? If it's an OEM orange or blue box, just find a used one and test it...