Here's the lowdown on Joe's rolling stock:

-First half of first season: Customized Olds Toronado Roadster, built by George Barris' Kustom City. (His Intertect-issued company car, AFAIK.)

2nd half of first season-2nd season: '68 & '69 Dodge Dart GTS convertibles, one with a 340 and one with a 383 (All of Joe's Mopars were dark green with black tops & interiors...the Darts also had black-painted grilles & Cragar S/S wheels)

-3rsd season: '70 Plymouth 'Cuda convertible with a 340 (per nameplate on hood)

-4th season: '71 Plymouth 'Cuda convertible with a 440 Magnum (per nameplate on hood).

-5th & 6th seasons: '72-'73 Plymouth 'Cuda 340 convertible. (Likely the '70 updated with later front/rear end parts, as Chrysler stopped making 'Cuda convertibles after '71.)

-Last season: ''74 Chevrolet Camaro coupe. (By then, Chevrolet had replaced Dodge as the show's vehicle supplier.)

Also, Joe's secretary Peggy drove current-model small cars (first a '69 SIMCA sedan , then a '72 Dodge Colt, then a '74 Chevy Vega)...and the other character's cars/cop cars were either current-model Dodges/Chryslers/Imperials, or Chevys (for the show's last season).