A character name in credits is intentionally misspelled.

Rating: Null/10 (28 December 2016)

Perry Lopez' character name in the movie is not Petuko. it is 'Pachuco'! An inferred slant as to Lopez' ethnicity in associating him with the Mexican subculture, 'Pachucos': one can clearly hear 'Big Joe'call Lopez 'Pachuco'. I know, I'm a South Texan, born in El Paso and raised in Corpus Christi; I had to fight-off such during my Jr High years. I am sure that the LA based mega studio did not want to inadvertently incite racial tensions in denigrating such ethnic groups thereby the intentional misspelling in the credits. A subliminal twist on pronunciation I guess; as to what is printed vs what is heard. It is quite obvious that screen writing decided to base character names on trait: Big Joe/Little Joe (obvious), Crapgame (grifter or con artist), Oddball (obvious), Cowboy (Texan), Mulligan (bad shot), Babra (Barbara) and Petuko (Mexican: audibly, Pachuco).
Wikipedia: Pachuco
Pachuco refers to a particular old school subculture of Chicanos and Mexican-Americans associated with Zoot suits, street gangs, nightlife, and flamboyant public behavior. The idea of the Pachuco – a Zoot-suited, well-dressed, street-connected flamboyant playboy of Hispanic/Latino heritage – originated in El Paso, Texas, and Ciudad Juárez, Mexico, had moved north, following the line of migration of Mexican railroad workers ("traqueros") into Los Angeles, where it developed further.
The origin of the term "Pachuco" is uncertain, but one theory connects it to the city of El Paso, Texas, which was sometimes referred to as "Chuco Town" or "El Chuco". People migrating to El Paso would say, in Spanish, that they were going "pa' El Chuco". These migrants became known as Pachucos. The name "Pachuco" is quite possibly derived from the name of the city of Pachuca, the capital of Mexico's Hidalgo state. There have long been migrants from Hidalgo state living in Texas.