First time start - no go

Thanks, I used a compression tester when bringing up #1 to TDC. That should confirm it is ready for firing too, correct?
Thee ballast resister is stock and probably the one in place when it was a slant 6. I'll try the jump direct to the coil + and see if that works.
The rest of the wiring is unknown, I have headlights, signals, hazards, interior lights, so it seems to be all in place and working properly. No radio, so I can't confirm that circuit.

You would think so.....but I'd personally not trust that. IMHO: Make a check that is 100% sure: Check for which valve pair is at overlap on #1/#6 TDC and wire the distributor spark wires accordingly. That fact that you have backfires out the carb says you very probably have a timing issue somewhere. Once done, then make sure your distributor rotor is pointed very close to #1 or #6 when at the 0 timing mark. It ought to be slightly CW from the appropriate spark tower.

/6 ballast ought to be fine. Check resistance when disconnected and it ought to be almost 0 ohms cold... 0.6 ohms cold to be exact. But that is bypassed out of the circuit when cranking so should not matter.

Look at the number of prongs on the connection on the ignition module.... if 5 then you need a different ballast. If 4, you are OK with the present ballast.

Check your voltage at the battery when cranking and then check at coil + to see that you have about the same there. If so your ignition bypass circuit (which bypasses the ballast during cranking) is working.

Check the gap between the reluctor and the nubs on the distributor shaft with a non-magnetic feeler gauge to see if it is at .008". (BTW, 3 thicknesses of standard weight printer/copy paer is about .009"...)

As said.... jumper battery voltage direct to coil + and see. But if there are other wiring issues, then the power to the ignition module may or may not be good.

BTW, you can't get valid the voltage readings at the coil + with this electronic ignition system with the engine not running. So the 4 volt reading may or may mean anything.