Not just trucks... there were a lot of Chevrolet cars that had the 250's in them too.
The 250 was used on the following vehicles:
1966—1984 Chevrolet (passenger cars to 1979, trucks/vans to 1984)
1970—1976 Pontiac Firebird
1970 Pontiac Tempest
1970—1976 Pontiac LeMans
1968—1969 Buick Special
1968—1972 Oldsmobile F-85
1975—1976 Oldsmobile Cutlass
1971—1975 Pontiac Ventura
1968—1971 Buick Skylark
1973—1975 Buick Apollo
1967—1979 Chevrolet Camaro
1969—1979 Checker Marathon
Ref. Article:
https://en.wikipedia.org/wiki/Chevrolet_straight-6_engine