Small Block Chevy Engine Block Identification

General Small block Info | Small Block Casting Numbers | Block Casting Date | Engine Code Stamping | Casting Clock Code
VIN Code Format | Camaro Specific Engine Codes | Small Block Suffix Codes

General Decoding Information
This topic can be somewhat confusing, especially with the amount of information available and the interpretation of it. The primary pieces of information you'll decode are the Engine Code and Partial VIN. You can decode the casting number. And you can check dates. The engine code and partial vin # will accurately nail down whatever the thing is rather quickly, and the other information will fall into line with that.

To QUICKLY IDENTIFY A CHEVY ENGINE CLICK HERE - for decoding engine codes.

This page has basic information on it, but it's a portion of the Small Block Chevy numbers information. The Engine Code page is where this topic is further detailed.

"Numbers Matching"
This is my opinion, and the generally accepted norm:
When people say "It's numbers matching" - what they mean is the engine (or other component, i.e the transmission) can be MATCHED to the vehicle it was originally used in. This match is done via the PARTIAL VIN stamp on the component. The partial VIN will match the vehicles VIN. If it does - it's "numbers matching", otherwise - it's not. done. end of story.
Some folks use these terms loosely, or will say "numbers correct" or something to that effect. But numbers correct is not numbers matching. Again, it either matches or it doesn't. If it doesn't match - is it correct?
Numbers matching is important when you're trying to decode a Z28 or Super Sport where the VIN won't identify the vehicle as such. You need to decode the engine and see if it matches the vehicle, and if the code signifies Z28 or SS equipment.
Lastly, in extreme cases, you'll want to verify the numbers stamped onto the component were the ones stamped into it originally and aren't restamped.
The point of this article is to help you figure out how to decode stuff.

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.
Click here for Chevy Engine Code Listings

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)
Another example: T0830CTY - (T = Tonawanda, 08 = August, 30 = 30th day, CTY = 1970 396 Camaro, 375 hp, 11.0:1, TH400)

CodeEngine PlantCodeEngine Plant
FFlint (Motor)SSaginaw Service
H HydramaticTTonawanda
KSt. Catherines, OntarioVFlint (Engine)
(McKinnon Industries Canada)
MGM of Mexico

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. Chevrolet issued technical service bulletins to indicate which engines were to recieve a vin stamp, so who knows what could have happend (or not happened).

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

For a list of assembly plants, click here.

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. Anyways, that's what that circle thing is (if you happen to see it on something).

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

  General Engine Block Specifications
While 6 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 just that,. otherwise 2 or 4 bolt can mean either design...

Chevy Small Block - 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 CIDLow PowerHigh Power Main CapsComments

1980-85 140029 350 - - 2 car
1973-803308174001501802car, truck
19753559092621101102car, 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 283170 315 2 car, truck
1956-67 3756935 283 - - 2 -
1962-6537828703272503752car, truck
1956-67 3789187 283 - - 2 -
1962-67 3789817 327 210275 2 car, truck
1961-6237899352831703152Late 61 car & vette
1962-673790721283 1702202Chevy II
1964-6737913623272503002Replaced 3790721
1958-6337942262831701952Car & truck
1968-69 3794460 327 250 250 2 truck
1968-69 3814660 327 - - 2 F A
1968-69 3814660 302 - - 4 Camaro, Z-28
19633830944327-3002-
1956-67 3832338 283 - - 2 -
1964-6638348102831952202Car, truck & marine
1962-6338348122831701952car & truck
1958-62 3837739 283 - - 2 -
1964-6838498522831952202car & truck
1956-67 3849859 283 - - 2 -
1956-67 3849935 283 - - 2 -
1964-67 3858174 327 - - 2 car, truck
1968-76 3855961 350 - - 2 car
1964-6738581743272753502Full, A & Y
1964-6738581803272503002-
1962-67 3858190 327 - - 2 -
1965-6738621942831952202Chevy II
1962-66 3864812 283 230 - 2 car, truck
1964-673868657327 300 - 2
1962-673876132327 - - 2
19633889935283 - - 2 truck
196738926573022902902Z-28, small journal
196738926573272103502car & truck
196738926573502952952Camaro
1968-693892659327 210 - 2
196738969442831951952replaced by 307 in 68
196738969482831951952identical to 3834810
196739033523272103502cars only
1969-803911460350 - - 2A
1968-733914635307 - - 2car
196839146363072002002car & truck
1968-693914638327 - - 2
1968-733914653307 - - 2A
196839146603272103002cars
196839146783022902902/4Camaro, Z-28
196839146783272103502car & truck
196839146783502952952Camaro/ChevyII
1965-673932288283 -- 2A
1956-673932338283 -- 2
1974-753932368350 -- 2
1969-733932371307 -- 2 car,truck
1969-733932373307 -- 2 car,truck
196939323863022902904Camaro Z28
196939323863272102102Camaro
196939323863503003504
196939323883022902904Z28
196939323883503003004cars
1968-693933100327 - - 2
1968-693933180327 - - 2
19683941174307 - - 2truck
1956-673949852283- -2
1970-8039515094001502652/4car,truck
1970-7339515114002552654B & G body
1962-673953512327--2
1968-693955618327--4 A,F,Vette
196939566183022902904Z28
196939566183272352352fullsize
196939566183502503502/4cars
196939566323072002002car & truck
1969-763958618350--2 A
1962-633959512327250-2
1956-673959532283--2
19683970010327--2 A
1969-7939700103501853702 or 4car, truck, Vette
1970-7339700143502003002/4LA built Camaro
1969-7339700203071152002car,truck
1969-7239700243071302002A,F,X
1968-766259425350 ---car,truck
1980-8414010201305--2car,truck
1980-8414010202305--2car,truck
1980-8414010203305--2car, truck
1980-8214010205267--2-
1980-8514010207350--4truck
1980-8514010209350--4truck
1978-8614010231305--2 -
1979-8214010280267--2 car
198214011064 350-- 4 Chevrolet, high tin
1979-8214016375 267-- 2 -
1979-8214016376 267-- 2 car
1978-8514016379 350-- - car, truck
1980-8414016381 305-- 2 car, truck
1978-8814016383 305-- 2 -
1979-8214040205 267-- 2 -
1978-8614049047 305-- 2
1986-9414079287 350-- -
198714088526 350-- 2 Camaro
1986-9414088548 350-- - -
1986-9214088551 305-- 2 -
1988-9414093627 305-- 2 -
1986-9414093638 350-- -
1988-9414094766 305-- 2
1986-9414101148 350-- -
1987-8814102058 305-- 2
1969-8514316379 350--2


Camaro Engine Code Stamping Numbers
Dropbox contains Camaro engine suffix codes for year selected.


Last updated: 9/14/2012
Author: MadMike Maciolek

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