The terminology and the slang usage of Stovebolt refers to three different things:
1) A bolt with a slotted head, used in the assembly of wood-burning stoves constructed from sheet metal.
2) A nickname for the inline six-cylinder engine made by the Chevrolet division of General Motors. So called because the valve cover, lifter cover and timing cover, utilizes a fastener that resembles a stovebolt.
3) Chevrolet-branded cars and trucks that were equipped with the inline six-cylinder engine.
The original usage of the term stovebolt applied to a bolt with a slotted head. This particular bolt design was often used as a fastener on wood-burning stoves that were fabricated out of metal sheets, which were very common in the first half of the 20th century. Therefore, any slotted-head bolt that looked similar to the bolts in wood-burning stoves became referred to as a stovebolt.
The original Chevrolet straight-six engine is referred to as a Stovebolt or Stovebolt Six because the 1/4″ × 20 slotted-head bolts on the valve cover, lifter cover and timing cover of the engine resemble the aforementioned slotted-head bolts. Thus, the slang term or nickname of Stovebolt was given to the Chevrolet straight-six engine.
The Chevrolet straight sixes were available in vehicles from the 1929 to the early 1960s. The later 1960s engines no longer used the slotted-head bolt (even though a lot of the design and layout was similar to, or derivative of, the earlier engines) and are not considered by old-Chevrolet enthusiasts as Stovebolt Sixes.
Since the Stovebolt Six was used or available in almost every Chevrolet vehicle offered during the production run of the engine, the term Stovebolt also became synonymous with Chevrolet-branded automobiles and trucks.
In the early 1990s, the Stovebolt designation started to be applied by old-Chevrolet-truck enthusiasts to refer more specifically to the Advance Design series trucks, which came equipped with the 216 and 235 engines. These trucks were produced from mid-1947 to early 1955. In old-Chevrolet-truck restoration circles, these are referred to as 1947 Second Series trucks to 1955 First Series trucks. The reason for this is that in 1947, Chevrolet was still producing the previous body style (referred to as a 1947 First Series), and in 1955, they had the newer body style (referred to as a 1955 Second Series) going into production simultaneously and out to the showrooms.
The specific guidelines for model years are as follows: 1947 to 1955 were of the early design; 1954s and 1955s saw a design change to the trucks, a one-piece windshield and a different hood being the two most prominent features; and in late 1954, a new bed design was introduced. The 1955 models had a midyear changeover to a totally new design, giving them the code Second Series—the First Series being the previous design, and the Second Series being the 1955–57 design.
Stovebolt definition from Chevrolet Motor Division, Media Archives.
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