Hi TKM,
If you change your mind and want to go the electric fan route, in my opinion there is no better fan than a Spal fan and the shroud sold by Antique Air (made for the AD truck) is hard to beat (although some claim to have made their own using commercial size cookie pans). I have one connected to an adjustable thermostat switch and this allows me to adjust any running temperature I want. I also have a 3 core aluminum radiator. In DFW we have summer pretty much 300 days a year (it is currently 84 degrees here and that is our "autumn") so driving in city traffic means you need mucho airflow. It has been a while since I was in Detroit. Main thing I recall is your summers were shorter but pretty humid. Good luck.

~ Jon
1952 1/2 ton with 1959 235 | T5 with 3.07 rear end