[nuch_ss396]

Steve,

I've never heard that 3 vs. 4 core radiators used different
fan clutch assemblies. As I mentioned, I do know that the
SB & BB are different lenghts and many use the SB clutch which
puts the fan too close to the radiator. I wish I could
remember the two lengths ( SB and BB ). I'm sure someone
on this board knows or can take a quick measurement.

Since you mentioned COPO, I'm assuming you're doing a BB car.

Steve