OK everyone, we have a win! I removed the T slot restrictors which Gary Williams said he never used and its a different car now. Stumbling is gone completely. It cruises between 14 and 15 afr steady as a rock. This also affected idle. Now I have 13.5 afr in park and 14.5 in gear with 150 rpm change. I put back the 76 IAB and stayed with 28 MAB.
WOT is 12.8-13.0 which is on the high side but its almost freezing temp here so probably this leans things out a bit, same with cruising. I have no air cleaner on it yet also.
Weather to drive is almost over so not much tuning can be dune further but I'm impressed on how it runs. I will have a 50 miles trip to storage tomorrow so I will report on how it works in more detail. I will work on it but only on some weekends. I got all the stuff for metering blocks mods, so we will probably come back to this as well.
I need to make a movie from driving so you can see where I'm at for yourself. I will try tomorrow on longer drive.
I can now put in in 3rd and accelerate from stand still without any acting up.
The builder used 76 IAB and 36 MAB in these carbs.
I am at 75 square jets now and will go up to 77 but this day was a total win.
This thread is not over, I will update for sure.
Thank you, this forum is great place to be.