When Mannix was chasing the motorcycle in the dirt the hood of his car was ajar, but when he lost the motorcyclist and was stopped the hood was fully closed.
Two different 1974 Chevrolet Camaro Type LT's are used in this episode. The Camaro parked in front of Mannix's office, the one used at the crime scene, the one one used early in the chase scene, and the one used at the marina have bumper guards. During the chase scene and after Norman Thomson is shot, the Camaro has lost it's bumper guards. This same car without bumper guards is used for the remainder of the chase.
When Mannix is chasing the motorcycle across the dirt and grass, the tires are squealing the whole way.