The only thing I can think of is that the mixture is off.

Either that you've got oil leaking into the cylinders, but that doesn't usually reduce under acceleration.

Is it "running too rich" (black/grey) smoke, or is it "burning oil" (blue) smoke?

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1946 Chevrolet 3600 - "Old Number Seven"

Cavalry's Here. Cavalry's a frightened guy with a rock, but it's here.