B&M Converter is bad

Ok gentleman, I have been very busy and was finally able to get the car back together with the new carb, plugs, wires, cap and rotor.

I went with the Holley Street Dominator 670 carb and once fired up and timing adjusted to 10* to start I hooked up the vacuum guage. Its nice and steady now, maybe moves 1 to 1.5 on the vacuum gauge. Big improvement!

I set the carb up at 10* initial, adjusted the idle. Then tweaked the mixture. Took it for a drive and still cant do a brake stand.

Here is what I do know from when I was adjusting everything prior. The mechanical in the dizzy is 20*, after my mods to the cam plate. This gives me 30* total. So I will bump up the initial. Now if I get it all dialed in and Im still having the same problems with the way it drives what do you think the problem could be?