I found the thread Massboy had posted here--I guess it is the pulley assembly that is rubber dampened and bolts to the harmonic balancer,not the balancer itself that is different..
86' Harmonic Balancer/ Rubber Isolated 3 groove pulley
Deep down I have this tiny shred of hope that a shot pulley is the real issue with Dad's farm truck. It's not finger loose like the one posted above, but I'm intrigued by the thought of the rubber slipping. Hadn't thought of that before.

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