Here's an NOS '68 cowl plenum air cleaner from the collection of Jim Webb. The '68 version of this
air cleaner has an indentation at the front of the housing to clear the smog pump used that year.
The indentation at the back is to provide clearance for the distributor. Take the time to notice how
original versions of these air cleaners were painted. The coverage is hit-and-miss on the inside and
even in a few small areas on the outside. Also note that the rubber boot is stapled to the air cleaner
before it is painted so the rubber actually got painted along with the air cleaner itself. The stapling
of the boot to the metal is done by hand and varies from unit to unit. Some have been seen with
staples more neatly aligned than as seen on this example. Notice the taped seam on the bottomside
of the rubber sleeve. These cowl plenum air cleaners never came with any engine ID decals or decals
of any kind on them either as a service replacement part or as delivered with the car.
The four square openings indicate a small block Camaro air cleaner. Five square openings are found on the
cowl plenum air cleaners which were used on big blocks, typically Chevelles and full-size cars.
Here are some of the labels on the original box that this air cleaner was packaged in.