Need Help Quick!!

Ok...here's the deal. This is help for my friend, not 5.0 related, but general car knowledge should help explain this:

We're in the process of upgrading a 1970 Plymouth Duster (with a slant six) to an electronic distributor. For some reason, when in the cylinders, plugs 1 and 6 are not firing (a la no light from the timing light)...HOWEVER, when the plugs are removed and held against the body of the car for ground..they fire just fine. So we know the distributor is working, we just can't figure out why the plugs won't fire in the cylinder. We've checked and rechecked connections...and then checked them 20 more times. HELP!

He has to be at work early in the AM, and we've been fighting this all evening. ANY thoughts would be appreciated even if they seem foolish. We're out of ideas.

Thanks in Advance!
Eric

update:

OK...we got it running..and firing on all cylinders now. We treated it like it was flooded and left the butterflies open and it started running on three or four cylinders...then...out of nowhere...it was operating on all cylinders but the light was still not shining on plugs 1 and 6...but it was running smooth...sounded normal. I don't get it. Anyway, we just have to set the correct timing now and should be good to go...if anything else comes up I"ll be sure to come back...thanks guys

Eric