The reason I mentioned this is because I read a list of gas engine specs for all 1979 medium duty trucks and Ford had the 475 SD and the 477 TSD listed together with virtually the same horsepower and torque ratings. This totally confused me and I was curious about it.
There definitely was a 475. Don't take this as Ford gospel, it is just my understanding. It first showed in 1974 in the 880 series trucks as a lower cost version of the 477 to respond to the GM 427 truck engine. The F & L-880 trucks were offered from 74 to 77 when the 880 's were rolled into the 800 series trucks.The 475 was essentially the same as the 477, but it did not have the 100,000 mile factory Super Duty warranty. I am told it also had a different crankshaft, but that point I am not certain of.
It was marketed as a lower cost medium duty engine rather than the higher priced Super Dutys.
By now however, diesel was closing the door on the big gas burners, but they still are a lot of fun!
I saw a 475 in a 79 F800 yesterday. The decal on the valve cover said 477, but there were emblems on the side of the truck that said 475-4V. I know it was original because it was in a fire truck with 15,000 miles on it.