Fan clutch 2806070 needed

What is so special about this particular clutch fan????? wouldn't you be better off with the mopar viscous unit? please school me...
Its the concourse correct thing to do if your going that route, they are rare liquid filled for 69 Hemi's, 69 1/2 440 6bbl cars and a few 340 cudas. If you don't have a very desirable numbers car why bother, but if you find one you hit the mother load.

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