Chopping and channeling is a form of automobile customization in the "kustom kulture" and among hot rodders. The procedures are often combined, but can be performed separately. While chopping takes in only a car's

pillar A column or pillar in architecture and structural engineering is a structural element that transmits, through compression, the weight of the structure above to other structural elements below. In other words, a column is a compression member. ...

s and windows, the more involved work of sectioning a car is carried out on the entire lower body.

Chopping

''Chopping'' a car, known more fully as "chopping the top," goes back to the early days of hot rodding and is an attempt to reduce the frontal profile of a car and increase its speed potential. To chop a roof, a shop cuts down the pillars and windows, lowering the overall roofline. Some racers on the

dry lake A dry lake bed, also known as a playa, is a basin or depression that formerly contained a standing surface water body, which disappears when evaporation processes exceeds recharge. If the floor of a dry lake is covered by deposits of alkaline c ...

s chopped the tops of their cars so severely that the windows were only a few inches tall, and sometimes called "mail slot" windows. Roof chopping became popular with

drag racer Drag racing is a type of motor racing in which automobiles or motorcycles compete, usually two at a time, to be first to cross a set finish line. The race follows a short, straight course from a standing start over a measured distance, most ...

s for much the same reasons as it did for lakes racers, and was applied also to

custom car A custom car is a passenger vehicle that has been either substantially altered to improve its performance, often by altering or replacing the engine and transmission; made into a personal "styling" statement, using paint work and aftermarke ...

s, kustoms, and lead sleds. The first roof chopper is considered to be Sam Barris (brother of auto customizer George Barris), who chopped and customized his brand new

1949 Mercury The Mercury Eight is an automobile that was marketed by the Mercury division of Ford between 1939 and 1951. The debut model line of the Mercury division, Ford slotted the full-size Mercury Eight between the Ford Deluxe (later Custom) model li ...

. Barris also pioneered a more advanced form, removing the

B-pillar The pillars on a car with permanent roof body style (such as four-door Sedan (automobile), sedans) are the vertical or nearly vertical supports of its window area or Greenhouse (automotive), greenhouse—designated respectively as the ''A, B, ...

and turning the car into a pillarless hardtop in the process. Automakers themselves may lower the roofs of concept cars based on production models, as AMC did with its AMX-GT, to make them look sleeker and "racy", even if impractical for normal use.

Channeling

''Channeling'' is a modification that can be applied to cars with

body-on-frame Body-on-frame, also known as ladder frame construction, is a common motor vehicle construction method, whereby a separate body or coach is mounted on a strong and relatively rigid vehicle frame or chassis that carries the powertrain (the en ...

construction. To channel a car, a shop lifts its body temporarily off of its ladder or perimeter frame, cuts loose the floor and refastens it higher inside the body, and then lowers the body back over the frame. Thus the entire body rests closer to the ground without alterations to the suspension, giving the car a lower profile. In some instances shops must also modify chassis components, and so may be constrained by local laws as well as safety considerations. Channeling is popular among hot rod, lead sled, and

minitruck A pickup truck or pickup is a light-duty truck that has an enclosed cabin, and a back end made up of a cargo bed that is enclosed by three low walls with no roof (this cargo bed back end sometimes consists of a tailgate and removable covering) ...

enthusiasts, the last calling it body drop.

Sectioning

''Sectioning'' a car is removing a horizontal section from its lower body, lowering the remaining top section onto the bottom one, and

welding Welding is a fabrication process that joins materials, usually metals or thermoplastics, by using high heat to melt the parts together and allowing them to cool, causing fusion. Welding is distinct from lower temperature techniques such as b ...

the result back together, reducing the body's and thus the car's overall height. Like a top chop, it has the advantage of reducing a car's frontal area and

wind resistance In fluid dynamics, drag (sometimes called air resistance, a type of friction, or fluid resistance, another type of friction or fluid friction) is a force acting opposite to the relative motion of any object moving with respect to a surrounding flu ...

. This sort of bodywork is popular on minitrucks, race cars, customs, and lead sleds.

References

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External links

Rod & Custom Magazine article: Vintage Channel Jobs
Vehicle modifications