Kustoms are modified cars from the 1930s to the early 1960s, done in the customizing styles of that time period. The usage of a "K" for "Kustom" rather than a "C", is believed to have originated with George Barris.
This style generally consists of, but is not limited to, starting with a 2-door coupe and making changes such as:
The head and tail lights of a true Kustom may or may not be the original ones manufactured with the car. Some popular swaps would be putting Oldsmobile or Buick headlights in another model for example. Headlights, tail lights, antenna(e) are also subject to term and act called "Frenching", where the object is cut from the body, a "box" in the shape of the item is fabricated and welded into the original hole. The part is then installed back into the "Frenching Pocket" giving it a look of being recessed into the body.
Traditionally, "Lead", (a mixture of 70% lead and 30% tin) is used in bodywork of the area instead of modern polyester fillers or fiberglass, after the metal shaping is done to prepare for paint. "Leading" connotes a true Kustom "Lead Sled", which was started in the 1950s to imply a large, slow lead-filled car that was all flash and could not hold its own at the races. This was sometimes not the case however and certain Kustoms packed some serious punch under the hood. Today, however calling someone's car a "Lead Sled" will generally be taken as a compliment.
Grills are often changed on lead sleds as well. Some owners use pieces of other grills to Kustomize their own. For example, using a DeSoto grill in a '50 Mercury, or a LaSalle (Cadillac) grill in a '36 Ford, two of the most recognized and classic combinations of all time. "Flipper" style hubcaps are popular on Kustoms, such as '57 Dodge Lancer (4 bars), '56 Oldsmobile Fiesta (3 bars), '59 Dodge lancer or "Crabs" as they are said to resemble a crab, Other such as '57 and '49 Cadillac hubcaps are also acceptable and referred to as "Sombreros", '57 Plymouth "cones", etc. There were also other popular styles that were purely after market and never came factory stock on another car, like "Hollywood" flippers, or "Crossbars" for example.