The Black Magic fans come with their own hardmount thermostat, you just adjust it to come on at X temp. Unlike most after markets that you attatch to the rad with wire, the black magic mounst to the front supports, using the lower rad. bolts.

More than tread lightly. Leave it like you were never there, nor anyone else.
'90 X-cab 4.88's 33 BFG AT's, rr ARB, Headers, Ignition upgrade, cold air induction.
'91 X-cab 5.29's 315's BFG MT's, rr ARB, custom bumper and flatbed