Lead sled

In automotive usage, a lead sled is a standard production automobile with a body heavily modified in particular ways (see below); especially, though not exclusively, a 1949, 1950 or 1951 model year Ford or Mercury car. Auto body repair used to be achieved through the application of molten lead to damaged body panels, and the same techniques were adapted for aftermarket cosmetic modifications.

In order to be classified as a “lead sled”, the vehicle was subjected to most, if not all, of the following body style modifications:

Chopped: cutting off the roof, removing four to six inches from the pillar posts and re-welding the roof back onto the car body.

Channeled: cutting the underside of the body to lower the entire body on the frame, usually by two inches.

French/Frenched/Frenching: recessing headlights, tail lights, license plates and radio antennas into the body for an exotic look.

Emblem removal: all original manufacturer's emblems were removed as these were considered to detract from the vehicle. The thought was "anything that produces a hiccup, a bulge or extrudes from the body is not aerodynamic and detracts from the smooth appearance of the vehicle." The object of the master craftsman is to make the body as smooth, sleek, and sexy as possible.

Trim removal: all factory trim was removed as these dressings detracted from the lines of the car.

Drip rail removal: rain drip rails were removed from the roof as they detracted from the smoothness of the vehicle.

Door handle and door lock removal: door handles and door locks were removed because these parts detracted from the smoothness of the vehicle. Electric solenoids and switches were installed in inconspicuous parts of the body, typically underneath the rocker panels, to provide alternate systems for opening the car's doors.

The entire process of removing badges, trim, and doorhandles was referred to as "shaving".

Grill modifications: the original grill was heavily modified, or substituted with the grill from a completely different make, model, and year car.

In the late 1940s and 1950s, plastic body filler and fiberglass did not exist. Instead, bar lead was used as a body filler. A true craftsman pulled and pushed out dents with body spoons, hammers and dollies until the sheet metal was as straight as they could get it. Any sheet metal that was still slightly wavy, the bodyman heated bars of lead and flowed the lead onto the body with an oxygen-acetylene torch similar to work done by a tin smith. The bars of lead were what we today call “solder” but were not the wire material we are familiar with today, typically sold for electrical or plumbing repairs. The lead bars or strips ranged anywhere from a quarter of an inch to one inch in width and several inches in length.

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Wikipedia