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Chevy Small Block Engine Identification

General Engine Block Specifications
Six different bore size blocks have been produced, the small block engine can be classified into 3 bore sizes and 3 main bearing sizes. 283 blocks (3.875" bore, 2.3" main), 302/327/350 blocks (4" bore, 2.3" or 2.45" mains), and 400 blocks (4.126", 2.65" mains). In 1968 the main bearing saddles were increased in size from 2.3" to 2.45".

CID   Year   Bore   Main Cap
262   1975   3.671   2 bolt ONLY
267   1979 - 81   3.500   2 bolt ONLY
305   1976 - 96   3.736   2 bolt ONLY
307   1968 - 73   3.875   2 bolt ONLY
327   1968-69   4.001 (2.3" main)   2 bolt
350   1968-88   4.001 (2.3" main)   2 bolt
265   1994   4.001 (2.45" main)   2 bolt
302   1968-69   4.001 (2.45" main)   4 bolt
350   1968-96   4.001 (2.45" main)   4 bolt
400   1970-72   4.126 (2.65" main)   4 bolt
400   1973-80   4.126 (2.65" main)   2 bolt

Notes: 2 bolt ONLY means 2 bolts! You will NOT find a 4 bolt 305 block (made by the factory). Otherwise 2 or 4 bolt can mean either design...


  Engine Code Stamping Numbers
All engines are stamped with an engine ID code, consisting of assembly plant code, production date and suffix code. V8 codes are stamped on a pad just forward of the right side (passenger) cylinder head. 6 cylinder engines are stamped on the passenger side of the block behind the distributor.

The engine date must precede the car build date, otherwise something is amiss. Some engine machining operations (decking) will obliterate the engine ID.

Engine ID Code Example: V0101CLJ - (V = Plant, 01 = Month, 01 = Day, CLJ = Engine Suffix Code)

 
Engine Plant Code
Flint (Motor/6-cyl) F
Hydramatic H
St. Catherines, Ontario K
(McKinnon Industries Canada)
GM of Mexico M
Saginaw Service S
Tonawanda T
Flint (Engine/V8) V

 

Casting Clock
On some Saginaw blocks, intakes and exhausts a "clock" was cast into the block. The clock is a circle of 10 dots, one dot for each hour of a shift (usually 10 hour shifts). An arrow points to the beginning of the shift an another dot outside the circle indicates what time of day the cast part was made.

Casting Date
Small block casting date is located on driver side rear of block on flange forward of bellhousing. Big block on the right side of engine above the oil pan rails.

Casting Date Example: E038 - (E = Month, 03 = Day, 8 = Last digit of model year (1978)).

Month: A = Jan, B = Feb, C = Mar, D = Apr, E = May, F = Jun, G = July, H = Aug, I = Sep, J = Oct, K = Nov, L = Dec

VIN Code Format
The vin code format is stamped onto most engines. The format consists of divisional identification number, model year, assembly plant designation and vehicle serial or sequence number.
In 68-69 model cars, the serial (VIN) number of the car the engine was installed in is stamped next to, or under the engine code ID.
Starting in 1970, the serial number is stamped either above the oil filter, somewhere on the block pad (in front of the cylinder head), or on the transmission flange somewhere. 

VIN code format Example: 13N100001
(1 = Chevrolet, 3 = 1973, N = Norwood, 100001 = Production sequence)

 

Engine Block Casting Numbers

Notes (for below): "High Power" is the maximum rate HP this block was used for, "Low Power" is the lowest rated horsepower RPO engine the block was used in. "Main Caps" is the number of bolts holding the cap. A "two-bolt" main, or a four-bolt main. Four bolt main blocks are desirable in high performance applications because the extra strength of the additional bolts keeps the bottom end rigid and less prone to failure. However, a properly prepared 2 bolt main engine will work just fine (often times you'll lose a rod bolt before you break a crank because it's "only" a 2 bolt main).

 
Years Casting CID Low Power High Power Main Caps Comments
1980-85 140029 350 - - 2 car
1973-80 330817 400 - - 2 car, truck
1975 355909 262 - - 2 car, truck
1976-85 355909 305 - - 2 A
1975 360851 262 - - 2 Monza
1976-79 361979 305 - - 2 car, truck
1978-86 366245 350 - - - car
1982-86 366286 350 - - 4 Chevrolet, siamese
1982 366299 350 - - 4 Chevrolet, aluminium
1956-67 383810 283 - - 2 -
1967-68 389257 302 - - 2 Z-28
1968-73 391436 307 - - 2 -
1965-67 393288 283 - - 2 car, truck
1976-79 460776 305 - - 2 car, truck
1976-79 460777 305 - - 2 car
1978-79 460778 305 - - 2 car, truck
1979-82 471511 267 - - 2 car, truck
1976-85 581671 305 - - 2 A
1985-94 1489363 350 - - 2 -
1979-82 2135412 267 - - 2 -
1979-82 2404929 267 - - 2
1973-76 3030817 400 - - 2 car, truck
1958-61 3556519 283 - - 2 car, truck
1955 3703524 265 195 _ 2 car, no filter
1955-56 3720991 265 195 225 2 car, truck
1957 3731548 283 220 283 2 -
1956-67 3736935 283 - - 2 -
1957-59 3737739 283 220 290 2 car, truck
1958-62 3756519 283 230 315 2 car, truck
1956-67 3756935 283 - - 2 -
1962-65 3782870 327 250 375 2 car, truck
1956-67 3789187 283 - - 2 -
1962-67 3789817 327 210 275 2 car, truck
1961-64 3789935 283 230 315 2 car, truck, Vette
1966-67 3790721 283 - - 2 Chevy II
1964-67 3791362 327 300 300 2 Chevy II
1958-62 3794226 283 220 220 2 truck
1968-69 3794460 327 250 250 2 truck
1968-69 3814660 327 - - 2 F A
1968-69 3814660 302 - - 4 Camaro, Z-28, Vette
1956-67 3832338 283 - - 2 -
1956-67 3834812 283 - - 2 -
1958-62 3837739 283 - - 2 -
1957-66 3849852 283 220 - 2 car, truck
1956-67 3849859 283 - - 2 -
1956-67 3849935 283 - - 2 -
1964-67 3852174 327 - - 2 car, truck
1968-76 3855961 350 - - 2 car
1964-67 3858174 327 300 - 2 A
1964-67 3858180 327 250 - 2 -
1962-67 3858190 327 - - 2 -
1966-67 3862194 283 - - 2 Chevy II
1962-66 3864812 283 230 - 2 car, truck
1964-67 3868657 327 300 - 2
1962-67 3876132 327 - - 2
1963 3889935 283 - - 2 truck
1962-67 3892657 327 - - 2 car, truck
1967 3892657 302 290 - Z-28, small journal
1968-69 3892659 327 210 - 2
1962-66 3896944 283 230 - 2
1965-67 3896948 283 - - 2
1964-67 3903352 327 250 - 2
1969-80 3911460 350 - - 2 A
1968-73 3914635 307 - - 2 car
1968-73 3914636 307 - - 2 car, truck
1968-69 3914638 327 - - 2
1968-73 3914653 307 - - 2 A
1968-69 3914660 327 250 - 2 truck
1968-69 3914678 302 290 - 2/4 Camaro, Z-28
1968-69 3914678 327 210 295 4 car, truck
1968 3914678 350 210 295 4 cars
1965-67 3932288 283 - - 2 A
1956-67 3932338 283 - - 2
1974-75 3932368 350 - - 2
1969-73 3932371 307 - - 2 car,truck
1969-73 3932373 307 - - 2 car,truck
1968-69 3932386 350 300 350 4 LT1,4
1968 3932386 327 - - 2 A
1969 3932386 302 290 - 4 Camaro,Z28
1969-76 3932388 350 165 300 2 car,truck
1968-69 3933100 327 - - 2
1968-69 3933180 327 - - 2
1968 3941174 307 - - 2 truck
1956-67 3949852 283 - - 2
1973-80 3951509 400 - - 2 car,truck
1970-73 3951511 400 - - 4 truck
1962-67 3953512 327 - - 2
1968-69 3955618 327 - - 4 A,F,Vette
1969 3956618 302 290 - 4 Z28
1969-79 3956618 350 165 350 4 car, truck, vette
1969-76 3958618 350 - - 2 A
1962-63 3959512 327 250 - 2
1956-67 3959532 283 - - 2
1968 3970010 327 - - 2 A
1969-79 3970010 350 185 370 2 or 4 car, truck, Vette
1968-76 3970014 350 - - 2 car,truck
1969-73 3970020 307 - - 2 car,truck
1968-76 6259425 350 - - - car,truck
1980-84 14010201 305 - - 2 car,truck
1980-84 14010202 305 - - 2 car,truck
1980-84 14010203 305 - - 2 car, truck
1980-82 14010205 267 - - 2 -
1980-85 14010207 350 - - 4 truck
1980-85 14010209 350 - - 4 truck
1978-86 14010231 305 - - 2 -
1979-82 14010280 267 - - 2 car
1982 14011064 350 - - 4 Chevrolet, high tin
1979-82 14016375 267 - - 2 -
1979-82 14016376 267 - - 2 car
1978-85 14016379 350 - - - car, truck
1980-84 14016381 305 - - 2 car, truck
1978-88 14016383 305 - - 2 -
1979-82 14040205 267 - - 2 -
1978-86 14049047 305 - - 2
1986-94 14079287 350 - - -
1987 14088526 350 - - 2 Camaro
1986-94 14088548 350 - - - -
1986-92 14088551 305 - - 2 -
1988-94 14093627 305 - - 2 -
1986-94 14093638 350 - - -
1988-94 14094766 305 - - 2
1986-94 14101148 350 - - -
1987-88 14102058 305 - - 2
1969-85 14316379 350 - - 2


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