Cruising with a high stall converter

First, this could be a dumb question.

I'm planning on a fairly stout cam in my 340. 284/484 approx. My engine guy told me I would need to run a 2500stall conv minimum to make it work right.
Trans is a '70 727TF. I'm planning on running 3.91 gears and a gear venders OD unit. (I already have the OD). This will change my ratio to approx. 3.00 to1.

My highway rpm will be around 2k, give or take. Will the converter slip/try for higher stall? I need educated, and come to the experts.