Curt,
Good job you are taking on! I have also looked at one of those heads, cut up at a friends house. That T shaped throat did not look good for flow. I'd be surprised if you saw the 165-170 as is.
As shown in your other pics, there is certainly plenty of meat to be removed, with the walls being nearly .250 thick.
I like the idea of the the rear wall bump, maybe make it a ridge from top to bottom at the top of T. Maybe extend it out upto 3/4 of a inch. Also port the inside radius of the T to help the port.
Tom
