Excuse me for my "ignorance" in the posting of my last comment here. I should have clarified what I said by refering to what Tom in NO said shortly after what I had said.
Looking at the DC-8 from our (NWA's) standpoint, the airplane did not suit our airline at all. It proved unreliable, underpowered, overweight, and out of range of some of our key destinations. In short, we only took delivery of our DC-8's to tie us over until we received the first of our Boeing 707's. Once we had enough 707's, the fleet of DC-8's was withdrawn from service. The Boeing 707-100's proved their worthiness and usefulness to the corporation, and brought about the order of the Intercontinental series.
I guess I shouldn't have made such and "ignorant" statement, especially considering that I do remember seeing the DC-8's carrying passengers well into the 1980's. When this post first appeared, that fact had slipped my memory. I had just finished reading a book on the history of Northwest, and the topic of the DC-8 was still fresh in my head.
And Tom...thanks for your help with the matter.
Aviation is proof that, given the will, we have the capacity to achieve the impossible.