Thank you for this information. I have seen both yellow caps with black “Delco” writing and black caps with yellow “Delco” writing. When I attended the MCACN show in Chicago all the 64 Impalas, I seen were black caps with yellow “Delco” writing.A few batteries were reproduction and others were OEM/NOS batteries.
There was a car that was all original. Nothing was done to it everything was all original. Unfortunately, the engine compartment, I failed to take photos because I, amazed by its originality.