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Chevrolet V8 Crankshaft Identification (Group 0.646)
Small Block V8
Chevrolet used two types of crankshafts, forged steel and nodular
iron. A simple way to identify them is by checking the parting line.
This line was a result of the two halves of the crankshaft mold that
produced the crankshaft itself. On a nodular iron unit this line
is about 1/32-inch wide and is raised above the surface. The forged
steel line is anywhere from 1/4-inch to 1/2-inch side and is essentially
flush.
Chevrolet generally used the nodular iron unit on engines with low
to medium horsepower ratings and the forged steel in engines with
higher horsepower ratings.
The casting number is located on the rough surface of one of the
counterweights or between the bearing journals.
For crankshaft casting numbers, see
here.
283 - 1957 through 1967
The 283 crankshaft was basically unchanged from 1957 through
1967 although different materials were used, nodular iron and
forged steel, based on the application. All were a 3.00-inch
stroke and have 2.00-inch rod journals and 2.30-inch main journals.
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302 - 1967 through 1969
The 1967 302 crankshaft was a small journal (2.00-inch rod journals
and 2.30-inch main journals) while all 1968-69 302 crankshafts
are large journal (2.10-inch rod journals and 2.45-inch main
journals) and all were 3.00-inch stroke. All are forged steel
and Tuffrided. |
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327 - 1962 through 1967
All 1962-67 327 crankshafts are forged steel and have 3.25-inch
stroke with 2.00-inch rod journals and 2.30-inch main journals.
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Early (1962-1964) flange design.
Late (1965-1967) flange design. |
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307 - 1968 through 1973
All 1968-73 307 crankshafts are nodular iron. This is interchangeable
with the 1968-69 327 crankshaft; only difference is the flywheel
flange shape. All 307 crankshafts were 3.25-inch stroke with
2.10-inch rod journals and 2.45-inch main journals.
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327 - 1968 through 1969
This crankshaft is a large journal and made in both cast iron
nodular and forged steel. All 300hp and below engines received
the cast iron nodular iron Same basic design as the 307
crankshaft with 3.25-inch stroke, 2.10-inch rod journals and
2.45-inch main journals.
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350 - 1967 through 1969
The only large journal crankshaft used in 1967 as was exclusive
to the SS350 Camaro and is forged steel. The 1968 & 1969
crankshafts were available in both forged steel and cast nodular
iron and have 3.48-inch stroke, 2.10-inch rod journals and 2.45-inch
main journals.
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400 - 1970 through 1975
All 400 crankshafts were cast nodular iron since the 400 was
not designed to high rpm use. The stroke and main bearing
journal diameter are different from all other small block
Chevrolet engines. The connecting rod journal diameter is
the same as all 1968 and later small blocks. The flywheel
flange is unique to the 400 crankshaft and uses dowel pins
to locate the flywheel/flexplate.
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Big Block V8
396/402/427 - 1965 through 1972
The 396 crankshaft is the same as the 427 crankshaft except
it is lighter due to the counterweight design. The third counterweight
on a 396 crankshaft is 3/4" wide, the 402 is 7/16"
wide, and the 427 is 7/8" wide.
Prior to 1968 all 396 crankshafts were forged steel. In 1969
the lower horsepower engines used a cast iron crankshaft and
have 3.76-inch stroke, 2.20-inch rod journals and main journals
were different sizes; journals 1 thru 4 are 2.7475-inch while
journal 5 is 2.7488-inch.
All 1965-1967 427 crankshafts were forged steel. For 1968 &
1969, only high performance 427s used a forged steel crankshaft
where low performance 427s used a cast iron crankshaft.
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454 - 1970 through 1975
The 454 crankshaft has the same flange as other big block crankshafts
but is totally different in design. Unlike the 396/402/427 crankshaft,
the 454 crankshaft is externally balanced at the front damper
and flywheel flange. The 454 crankshaft has a 4.00-inch stroke
but the same rod an main journal size as the 396/402/427.
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