Ford 400 timing tables

I am splitting this off from my old/main thread in order to keep issues separate. With the engine finally running okay, I wonder how to set timing. I found the specs for the original distributor and tried to mold them into a base table:
http://pic.armedcats.net/d/dr/dr_gri...04/less_sa.png

On the other hand, the MAP reading when idling in D is 55 anyways, so I wonder whether it'd be better to bring all the (simulated) vacuum advance in before that:
http://pic.armedcats.net/d/dr/dr_gri...a_map_0804.png

Which one would you use as a starting point? With the bottom one I did not expect any pinging or detonation yet, "only" one backfire through the intake on a sudden kickdown from idle when not in gear (which might even be not connected to the advance settings at all).
But then again, due to the car not having a fuel tank yet I've only tested the engine in Neutral.

EDIT: Spark plug gap is set to 0.050, matching a Duraspark-equipped later year Ford 400 engine.

55 in drive, what is it in park? the pop may be a need to increase the ae in the tps and map settings. it could also be the delay in pe a good run on the road giving the computer time to program some times changes a lot of things.

Thank you for your input!

I managed to tune out the backfire by switching to the second table. She runs und drives great with it. I thing I experienced some knocking cruising at 3000+ rpm, hard to tell without a knock sensor. I'll just dial timing back a few degrees in the higher rpm areas...

Also did a 100-mile drive and got logfiles, am tuning the fuel table as we speak...

Not being satisfied with low-rpm power delivery, I decided to do some research, as a friend rightly pointed out that most Ford V8 timing advice available online is geared towards the more common Windsor engine, while my car sports a Cleveland M-Block, which is a different beast altogether.

Luckily, there's nothing that hasn't been featured on Hotrod.com, and so I found this article about tuning a Cleveland-powered '70 Mustang. Accordingly, I decided to bring maximum timing in earlier and throw some more initial timing at her and to also cap maximum advance at 48° in accordance with another document I found online.
http://pic.armedcats.net/d/dr/dr_gri.../Spark_new.png

This really was a huge step in the right direction. She pulls much better from a standstill and more willingly accellerates at highway speeds. In fact, it's hard to maintain a sensible cruise speed - I forced myself to stay in between 80 and 85mph in order to not totally fuck up fuel economy - netted a respectable 13.5 mpg. If I were able to keep the foot off the pedal a bit more and maintain a more sensible 75mph, I think I might reach 14mpg easily.