Actual compression is under 7 to 1; What rpm are you running now at 60mph? I understand what you are trying to do running at peak torque. Question is will 200hp be enough to pull the rig up the grades you mentioned, and can you maintain that 2400 rpm without having to get into the secondaries on the carb.

The holley you run might not effect mileage as much as a spreadbore in regard to the secondaries, I don't know for sure.

As far as the torque curve goes, other info I have read from chrysler has 413 with 400 ft lbs at 2000 rpm. I'd say anywhere between 2k and 3k rpm and you should be running close to peak torque.