There are certainly a lot of things that can contribute to your problem, but the torque converter is not the first item that comes to mind.

The first 2 things that stand out to me with the information provided. A)the initial timing is a little low and the curve is a little slow. And B)the CarterBrocks are often a poor choice given their well deserved reputation for drive-ability issues.

Our big blocks really respond to timing. Throw 5* to 8* more timing at it and try a test drive. No full throttle blasts with that much timing, just a short drive around to see if it helps the stumble.

And see if someone has a known-good carb that you can borrow and try.