Car is an 86 NA, problem is a pronounced high freq vibration when revving in neutral or clutch in (no diff) vibration is primarily around 3K plus RPM. Of course it also vibrates when cruising down the road.

Ive tried 2 known good fans on the car but the vibration doesn't go away, unless I take the fan off completely.

Any ideas?

the water pump is new, and the pulley seems to be aligned just fine.

Thanks.