Engine Colors

old dog said
Doing a rebuild on a 1966 Dart GT Conv. with a 225 slant 6. Can not find any definitive word on the factory color for the engine. See other rebuilds on line in both colors, Tractor Orange/Red or MOPAR Blue. Any authorities out there?
Thanks

Red. As it gets old and used it can look more orange but it was red. Blue started in1970.