Hummm, I'm not sure what to say about your thought train. Considering the size engine and rated stall of the converter, which will change a little since the more torque you put into it the higher it stalls. Hence the cheap route of the use of the /6 converter behind a 440 big block trick.
A little porting on a 360 head IMO is not snuff even for what your telling me. *I think* it'll run out of head at or below 4000. Perhaps, speaking with one of our resident engine builders would yield better results. This is a route I have not taken. This is a route I would not travel.
I myself would look into a 360 to build on the side and do that engine for what you want.
OH! And what Moper said.