I have a 87 4000 s w/over 200 k. I have replaced both frt. axle assys, and both rear wheel brg. assys.

Still...when I turn left it make a whirring noise like a wheel Bearing in the frt. Rt turns silent.

I had replaced the frt left brg in my old 87 4000 and it turned out to be the rear (for a similar noise....) sound like the frt left brg? ;-(!

 

It could be your control arm bashings try rolling that single wheel toward the cab of the car and the bumper of the car while the car is on the ground.