@tibby , thanks for the chart. It seems that the chart only shows Rosso Comp colors. It seems that there are several (4-5?) codes for the same color. Why? Do they actually look different?
I am more interested in the Rosso color, and if there are variations in that color, through the 4C production years.
@Alfanut , the reason for my interest is that I am soon painting a 74 GTV project. Originally a red car; probably code 501. It has been (re)painted twice and each time it got brighter red; more orange(?), like Coke red. I can see (compare) the original red to the repaint reds, and the original is noticeably darker-deeper red. More like blood. Years ago I parked next to a Rosso 4C and made some comparisons. I remember thinking that this was the red that I wanted. I have no idea what year the 4C was, and want to make sure that I choose the correct code. Hence my inquiry. Thanks to everyone for their help.