Chevrolet Big-Block engine
The Chevrolet big block is a series of large
displacement V8 engines that were de-
veloped in the USA during the 1950s and
1960s. As American automobiles grew in size
and weight following the Second World War
the engines powering them had to keep pace.
Chevrolet had introduced their popular small
block V8 in 1955 but needed something lar-
ger to power their medium duty trucks and
the heavier cars that were on the drawing
board. The decision was made by Chevrolet
to develop an all-new design for large-dis-
placement use. This engine family had two
generations, the "W" series, and the Mark IV
series.
Generation 1: "W" Series
The first ever production big block V8 Chev-
rolet engine was the "W" series, released in
1958 for passenger car and truck use. This
engine was an overhead valve design, with
offset valves and unique scalloped rocker
covers, giving it a distinctive appearance.
The "W" series was produced from 1958 to
1965, with three displacements offered:
348 cubic inches (5.7 L), available from 1958
to 1961 in cars and through 1964 in trucks;
409 cubic inches (6.7 L), available from 1961
to 1965; and 427 cubic inches (7.0 L), avail-
able only in 1963.
As was the norm at the time, the "W" en-
gine was of cast iron construction. The block
had 4.84-inch (123 mm) bore centers, two-
bolt main bearing caps, a "side oiling" lubric-
ation system (main oil gallery located low on
the driver’s side of the crankcase) with full
flow oil filter, and interchangeable cylinder
heads. Heads used on the high performance
409 and 427 engines had larger ports and
valves than those used on the 348 and the
base 409 passenger car and truck engines,
but externally were identical to the standard
units. One minor difference between the 348
and 409/427 was the location of the engine
oil dipstick: it was on the driver’s side on the
former and passenger’s side on the latter. No
satisfactory explanation was ever presented
for why this seemingly useless change was
made. However, it was a fairly reliable way to
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