do a google search on "taurus fan". There are a couple of great wiring diagrams out there. I used the NAPA golf cart relay (cont. duty), has worked great.
I used a threaded port on the driver side of the 258, it had a plug in it, and went right into the water jacket. Just forward of the vertical centerline of the carb, maybe about 1/2 way down the side of the lock.
I ended up putting mine in as a pusher, as I didn't have room for the taurus betw. the motor and rad. I made a spacer and moved rad back about 1.5 inches, more or less. Cools fine, will cycle on hottest days.