I will be completely tearing down the engine and transmission for rebuilding and blueprinting. What upgrades to camshaft, throttle body, cylinder heads (porting), PCM, and torque convertor do you recommend to improve towing without affecting emissions greatly. I already plan on a 3" exhaust after the cat and 4.10 gears for the Dana 60.

Starting from scratch? About the only thing I would reuse would be the block and engine dress, a 9.0 comp 408 with RHS heads, small cam like the mopar R/T or R/T +10, 2 barrel M1 intake with a 52-55mm TB and a set of the old Mopar/PPH try-Y headers would be a good towing motor.

About anything you do to a 360 mag to pick up HP/TQ is going to move the RPM range higher, with the 4" crank it will move the RPM range back down closer to what the stock 360 has but still have more power.