Lance, if the condition of the oil is that bad an immediate oil change is warranted. Be sure to remove/replace the oil level sender after the oil is drained. You may want to research some additives that could be used briefly to "clean" the engine internals before changing the oil.

At idle does that engine make any strange noises, such as very noisy hydraulic valve lifters? It's a shame the owner has abused that vehicle.

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Fred Hoelzle