on my big block burban, i run 2 14" staggered up and down to fit. i know the BB radiator is bigger, prolly won't be able to run 14"s on a SB. i use an adjustable controller with relay setup. it uses a probe in radiator and has a small knob to adjust the temp to turn on. i didn't trust the one relay to run both fans, so i i split the 12v positive output and used that to signal 2 seperate relays that actually run the fans. that way there is no actual load on the thermostat, and if a relay quits, you only lose one fan. the controller also has a 12v positive input that you can use to manually turn them on. i used that for the A/C, although you must use a signal that stays hot at all times A/C is on. if you use a signal wire that cycles with the compressor, the fans will also cycle. i then wanted an override switch on the dash, so i again tapped into the 12v signal wire on the thermostat from a toggle i mounted in the dash. i had to use a diode on the a/c side though, if you don't, you'll turn on the a/c system when you hit the override. confusing, i know, but it's worked flawlessley for almost 2 years.
