So these cars will have "City of Miami" on the letterboard. My understanding is that IC only put the train name on the letterboards for a while - does anyone know what years that lettering is good for?
According to ACL Passenger Service- the Postwar Years (Goolsby), ACL 247 had "City of Miami" lettering from 1949 until 1971, and has a picture dated 1971 on a run to NYC (far from its IC home). A second car (248) was painted in the scheme in 1954, also (per the book) until 1971. They also painted several heavyweights in IC colors (but with Atlantic Coast Line on the letterboard) for use in Seminole consists.
Here is a City of Miami consist from an ACL public timetable dated April 1956 (no headend or numbers shown- and only shows the train as it looked on ACL territory)
10-6 Chi-Miami
4-4-2 "
3DBR-1C-1DR-Lounge Chi-Miami
6-6-4 Chi-Jacksonville
Coach 56 seat Chi-Jacksonville
Diner Chi-Miami
Coach 68 seat "
Coach 52 seat "
Coach 54 seat "
Coach 54 seat "
Coach 54 seat St Louis-Miami
Tavern Lounge Obs Chi-Miami