Stock distributor? Really?
If you didn't have at least 18* on it, you aren't even close. That thing won't idle worth a darn with the total timing method and a stock distributor. The big rpm drop is the first clue, idle mix screws not killing it is second... it's not on the idle circuit.
I'll bet it will want 22-24 initial and 12-14 mechanical to hit your number. Go out and turn the distributor CCW when running, if it picks up rpm, it wants the timing. That should idle in the 850-900 range and not drop more than about 100 rpm in gear.
Unfortunately, lots of engine builders are terrible tuners for anything other than WOT. Street manners why you need that... :)