The original slant 6 block in my '64 Dodge D100 Sweptline was yellow. It was my grandfathers truck and he bough it new in '64 when I was two years old. I remember, years later, sitting on the fender well as he changed spark plugs. I remember a lot of yellow. When I pulled the block out a year ago to rebuild it, I pressure washed it. Guess what, I uncovered the original yellow paint.