One step forward, two steps back!

Alright, hard one to explain in english, me being a Swede and all

First: Duster, 1965-273, 340 cam, edelbrock 4bbl intake and 600 carb. eletronic ignition, 727 auto, 8 3/4 with 3.31 sure grip, headers

I've had some trouble tuning it and have had a stumble and hesitation from time to time before it picks up revs. I have done my homework here and have checked for vacum leaks, played with timing and tuned the carb and gotten it to run very well, but still had a bit of hesitation from zero to full throttle.

Well, today I think I cured it. There was a little vacum leak that I had managed to miss. I fixed that and took it for a spin, responded very well and pulled strong.

So far all good! But, when coming to a red light and braking and coming to a stop in gear the engine died on me. it fired right up again though. Then it happened two more times the same way, me braking coming to a stop in gear, engine died (never done this before). The weird thing is, the last time I lost all electrical power when it died on me. It would not turn over. I though It might been because I was not totally in park, so I tried neutral, but nothing. Then I realised I had no power at all. Then after a few moments the oil pressure lamp came back, so the power had returned and I fired it up and took it back to the garage.

I dont know if it could be related but I had set my initial timing really high before I found the vacum leak, around 18-20*. That is all I really did today besides fixing the vacum leak (it was the vacum nossle on the driver side of the edelbrock. my plug had dried up and leaked). The motor did seem to like the timing though because it ran better then ever today. Just wondering of it could be related, but cant really see how.

I've tried to explain best I can, hope it's somewhat comprehensible