To run a larger fan, pull battery power right off the starter with heavy wires to the fan, use a relay to trigger it on and off. Might save you from moving the battery.
A 12" might not be enough fan, it will only pull air from a 12" diameter of the radiator unless you mount it out away from the core and use a shroud. This will let the fan use the whole core.
Mechanical fans will out perform a electric every time, a mechanical fan with a clutch will work even better. I would use electric as a last resort.
Always use a thermostat, they not only control warm up but also water flow rate.
Tune up plays a major role in engine heat, timing needs to right along with fuel mixture.
Joe
