My Leaning Tower

The red used on V8s was in many cases not the same as the red used on Slant-6s, which is one reason why you can go through a whole bunch of brands of "Chrysler Red" engine paint and not get a satisfactory match. The other reason is that the factory paint fades, colour-shifts, and darkens with age, thermal cycling, and exposure to oil, gasoline, and other underhood chemicals.

See here.