+1000 if you have underdrive you need to upgrade to the 3g style alternator before you go electric fan or your lights and shit will go dim at idle when its on.....
I have my fans wired so they run all the time with the key on becuse I was too cheap to get a temp switch
ignition hot for a trigger on a 40 amp relay from a power distribution block then a 30 amp fuse then on to the fan its easy to do you can stop and look at mine sometime if you want