What's the pro and cons of castiron vs aluminum water pump? My 75 LTD with a 400m engine overheats at idle. Was thinking about getting a high flow water pump as I learned these engines are prone to over heat at idle. I see cast and aluminum options as well as a aluminum timing cover. Original timing cover is castiron. Should I not worry about it, use aluminum pump with iron cover or switch cover aswell?FYI, radiator is a new 3 core, hoses are new. Thermostat is new and at 195°. I have a 180° on hand. Have a 7 blade fan from a 460 and new clutch.