"Converter change" how much improvement...

I have noticed this cam comes on strong around 2K or there abouts,

Then would a 27-2800 stall be a bit on the high side.

If you're already making good usable torque at 2000, you'll likely be wasting some of that with a higher stall. That cam has small @ .050 numbers. I personally wouldn't go higher than a 2500. But thats just my opinion.