The 478 was original to the truck, but I don't remember the series, but I think it had to be an 8500 series. I bought it in the 80's to jockey trailers around town. I think it was probably the same cab as they used in the 9000 series. I even went so far as to put a Bartlett hydraulic 5th wheel on it. We quit using it when all of our road tractors had air ride and suspension dump and insurance got too high on something that never got more than 5 miles from the yard. I sold it along with a load of salvage around 5 years ago. I wish now I had cut it and kept the components. I am now looking for a steering axle and a heavy 2 speed with Dayton wheels on straight air to put under my 1957 600 GMC. I don't care about the 478, but I am sure someone on a forum like this would have been happy to get it. One of the local feed stores had a 637 in a conventional with drag axle. By then I had all Cummins with twin screws and didn't pay much attention to it. The family sold the feed store recently and there were a bunch of old trucks around back. I think they were scrapped because they even removed the grain tanks in an attempt to sell the building. I'm not so sure you would have wanted to trade the 637 for a 6v53. We have one in our yard mule and its fine, but I'm not so sure its got the power you would have wanted.
