The original use for those scoops were on the Ford F700 and larger trucks of the late 50s/ 60s. and into the early 70s.
Pontiac then used them on the super dutys
The trucks they were available on are:
1957-1963 F700-1100, T700-950, B700-750.
1964-1969 F750-1100, N750-1100, T750-950, NT850-950.
1970-1972 F750-950, B750-950, LN600-700