Can't start my 408!

I installed a 408 Stroker in my duster, and am having problems getting it to start. It will crank over fine, and fire occasionally, and I have bee able to get it to start before, but with some conditions:

When I got it started, the timing was way retarded, so much so that the mark did not show on the damper. Also, it was backfiring something aweful.

When I advanced the timing to about 10 BDC, the idle smoothed out, and as I was adjusting the carb, it died, not to be resurrected! It will still turn over, firing occasionally, but won't start.

When I unplug the coil wire from the dist, it will spark nicely when I turn the engine over, but something is weird. I did some checking of the voltages at the coil, and here is what I get:

Key in "Start" Position = 12 volts from + coil to ground.
Key in "Run" Position = 4 volts + coil to ground

Key in Off position: No Volts. However, when I check for continuity, I get 5 ohms (near straight wire to ground!) from the positive side of the coil to ground. Should there be a continuity between the positive side of the coil to ground ever?

Thanks!

Puzzled in AL