So I just installed a 360 back into my lil red and I'm now trying to get it fired up. I seem to have it all wired up right but I'm not getting any spark. I've checked with a test light and with the key on position I have power at the positive side of the coil, power at both sides of the ballast resistor. I've also swithed the ecu box out with new and installed a new distributor. I'm almost ready to take the engine harness out and switch it with one on a parts truck that I have that I know is good. The coil also came off a running truck as well. Any help on where to look now would be awesome, thanks!

Is the air gap right?

Maybe the pickup unit is bab.

Rotor in the dist?

The distribitor is new and came out of my cuda which was running so it should be fine.

If you have another running vehicle (your Cuda for example) you can swap your parts onto it one at a time to verify good parts. The other thing you can do is compare voltages through the system between the two.
I like to "bench test" with the distributor out but connected and grounded. You can spin the shaft and make sparks without running the battery down with the starter.

'79 318's have an EGR timer that will cause "no spark" when it goes bad...must be replaced or bypassed.

Just a thought...being a truck person you probably already knew that.

Checking the "start" side: take off the yellow "sol" wire from the starter relay to disable the starter to keep from unneccesarily running the batt down. Take off any/all wires from the coil neg primary terminal and with a jumper wire w alligator clips on each end/clip one to the male pri neg coil terminal and tap tap the other clip to ground repeatedly like Morse Code as a helper holds the key to "start" & if the coil secondary wire (dist end) held 1/4" from ground sparks this tells you the ign sw/coil/their supporting wiring (the "start" circuit) is good and that the prob is the ECU/ECU ground/dist pickup or one of their supporting wiring circuits. Holler back & more later. In a 5 pin ECU/4 male terminal ballast system (2) terminals in the ECU must be hot in "start" + bypassed 12V to the coil positive pri terminal