Strange Slant 6

So the white stuff was in the pipe at the motor end by the manifold? Well thats no good at all.That should be brown to black. White could be a contaminant. Sometimes coolant. Sounds like the engine went lean and the high exhaust temperature burned off all the carbon that usually accumulates there.And the excessive throttle used will build a lot of crankcase pressure, which I imagine pushed the oil out somewhere.Would you associate the power loss with a recent fill-up? Also note, that a plugged exhaust system will suck up power in a hurry.Similar symptoms, but doesnt usually come on like a switch.Its more of a gradual thing.Take a look at the exhaust pipe all the way back to the muffler. It might show a hot-spot,But the muffler is the usual culprit.