Engine ID Suffix Codes

Engine

Transmission

Notes
Code Size HP      
BB 230-1 140   Manual-3 Heavy Duty Clutch/A.C.
BC 230-1 140   Manual-3 Heavy Duty Clutch
BL 230-1 140 Powerglide   A.I.R.
BM 230-1 140 Powerglide   A.C./A.I.R.
BN 230-1 140   Manual-3 Overdrive/A.I.R.
BO 230-1 140   Manual-3 A.C./A.I.R.
CA 230-1 140   Manual-3 Overdrive
CB 230-1 140   Manual-3 A.C.
CC 230-1 140 Powerglide    
CD 230-1 140 Powerglide   A.C.
CM 250-1 155-L22   Manual-3 Overdrive
CN 250-1 155-L22   Manual-3 A.C.
CO 250-1 155-L22   Manual-3 Overdrive/A.I.R.
CP 250-1 155-L22   Manual-3 A.C./A.I.R.
CR 250-1 155-L22     A.C.
CS 250-1 155-L22     A.I.R.
CT 250-1 155-L22     A.C./A.I.R
DA 283-2 195   Manual-3 Overdrive
DB 283-2 195   Manual-4  
DE 283-2 195 Powerglide    
DI 283-2 195   Manual-3 Overdrive/A.I.R.
DJ 283-2 195 Powerglide   A.I.R.
DK 283-2 195   Manual-4 A.I.R.
DN 283-2 195   Manual-3 Heavy Duty Clutch
EA 327-4 275-L30   Manual-3/4  
EB 327-4 275-L30   Manual-3/4 A.I.R.
EC 327-4 275-L30 Powerglide   A.I.R.
ED 396-4 325   Manual-3/4  
EE 327-4 275-L30 Powerglide   L30
EF 396-4 350-L34   Manual-3/4 Heavy Duty Clutch
EG 396-4 375-L78   Manual-3/4  
EH 396-4 325   Manual-3/4 A.I.R.
EJ 396-4 350-L34   Manual-3/4 Heavy Duty Clutch/A.I.R.
EK 396-4 325 Powerglide    
EL 396-4 350-L34 Powerglide    
EM 396-4 325 Powerglide   A.I.R.
EN 396-4 350-L34 Powerglide   A.I.R.
EP 327-4 325-L79   Manual-3/4  
EQ 327-4 275-L30   Manual-3 Heavy Duty Clutch
ER 327-4 325-L79   Manual-3/4 A.I.R.
ES 327-4 325-L79   Manual-3 Heavy Duty Clutch
ET 396-4 325 TH-400    
EU 396-4 350-L34 TH-400    
EV 396-4 325 TH-400   A.I.R.
EW 396-4 350-L34 TH-400   A.I.R.
EX 396-4 375-L78   Standard A.I.R.
According to accepted production numbers, the SS (396) engines break down as follows:
2-door coupe/convertible L35 325hp base engine - 45,218*
2-door coupe/convertible L34 350hp high performance engine - 17,176
2-door coupe/convertible L78 375hp special high performance engine - 612

Note the above figures DO NOT mention the El Camino. While the El Camino was NOT available with the SS option the L35, L34, and L78 engines were available in the El Camino. These figures may very well represent the total number of 396 engines installed and do not take the El Camino into account or they may represent the KNOWN number of 396 engines installed in SS Chevelles and the number of El Camino installations is not known. It is known there were 2,565 orders placed for the L35 396-325hp engine.

* Since this engine was an option in the El Camino and standard equipment on the SS396, it can be assumed that there were 2,565 El Caminos ordered with the L35 V8 engine.

Examples of engine assembly plant ID stamped codes.

File Photo
Tonawanda ~ Sept 20 ~ 283/195hp 2-bbl Powerglide

File Photo
McKinnon Industries ~ June 16 ~ 283/195hp 2-bbl Powerglide

File Photo
Flint ~ October 21 ~ 327/275hp Powerglide with A.I.R.

File Photo
Tonawanda ~ April 21 ~ 396/325hp w/TH400 transmission
Note VIN derivative stamped at Kansas City final assembly plant.

File Photo
Tonawanda ~ June 9 ~ 396/325hp w/manual transmission
Note VIN derivative stamped at Kansas City final assembly plant.

Note: The engine ID pad was not painted when left the assembly line although it's often painted when engines are rebuilt during the course of their lifetime. Painting can also hide the factory broach marks on the pad making it difficult to determine if the block has been decked and numbers restamped.

It's interesting to note that the VIN derivative stamped on the engine pad was supposed to be stamped on the engine with a gang stamp holder assuring an even, readable VIN derivative. This wasn't always the case as numerous examples of VIN derivative stampings have been seen with the characters misaligned.

File Photo

Engine Block and Heads Casting Numbers

Engine Block Casting Numbers

The block casting number on small block and big block Chevrolet V8 motors is located on a ledge found at the rear of the block, most often on the driver's side. This ledge is below the deck of the block and the ledge forms the mating surface between the block and the transmission bell housing.

Block
Casting Number		 Engine Size Engine Horsepower Main Caps/Information
3892657 327 275 - 325 2-bolt
Used for most 1967 327 applications
3896948 283 195 2-bolt
Flint cast block
3903352 327 275 - 325 2-bolt
Used mid to late 1967.
3902406 396 325 - 350
375		 2-bolt
4-bolt
Used for late 1966 and 1967 years only due to change in oil galleys. Second design 396, no dowel pin on timing cover and last year to have this timing cover design and canister type oil filter. Casting date is located on the right lower side of the block near the freeze plug. this block also has the tall tower distributor casting boss in the lifter gallery.

File Photo
Block casting #3902406 ~ 396 2-bolt (325hp/350hp) or 4-bolt (375hp) main caps. 
Prevailing theory is the letter "P" indicates the block was destined for passenger car and not a truck.

File Photo
Block casting #3892657 ~ 327 (275/325hp) 2-bolt main caps.

Cylinder Head Casting Numbers

Casting Number Engine Size Engine Horsepower valve Size (intake/exhaust) - combustion chamber volume
3884520 283 195 1.72/1.50 - 60.530 c.c.
Pyramid casting symbol
3890462 327 275
325		 1.94/1.50 - 63.305 c.c.
2.02/1.60 - 63.305 c.c.
Double-hump casting symbol used through late May, 1967.
3917291 327 275
325		 1.94/1.50 - 63.305 c.c.
2.02/1.60 - 63.305 c.c.
Used after May, 1967. Same as #3890462 except it has temp sending boss (may or may not be tapped) and valve guide boss enlarged to 0.410-inch.
3904390 396 325 - 350 2.06/1.72 - 98.427 c.c. - oval port
No spark plug shield boss as with 1965 and 1966 cylinder heads. Used until January, 1967 when replaced with #3939802.
3939802 396 325 - 350 2.06/1.71 - 100.967 c.c. - oval port
Production began in January, 1967 through April, 1967 replacing #3904390 with redesigned combustion chamber.
3917215 396 325 - 350 2.06/1.71 - 100.967 c.c. - oval port
Late production replacement for #3939802. Temp sending unit boss present but not tapped until 1968 model year.
3904391 396 375 2.19/1.72 - 106.8 c.c. - rectangle port
Early production. No temp sending boss.
3919840 396 375 2.19/1.72 - 106.8 c.c. -  rectangle port
Late production. Temp sending boss and may or may not be tapped and two accessory bolt holes added. Domed casting symbol.

Engine Assembly Date/Suffix Code:
The engine assembly code looks similar to T0601ED. In this case the first letter "T" stands for an engine factory Tonawanda, an "F" or "V" for Flint or "K" for McKinnon Industries. The next two digits indicate the month of the year, in this example "06" or the sixth month, June. The "01" indicates the 1st day of the month. So what do we have so far in this example? The motor was assembled at the Tonawanda factory on June 1st. The calendar year itself is not given but remember that the engine assembly had to be manufactured and assembled before the car was built. What we have left is the "suffix code" which in this example is ED, a 1967 396cid with 325hp. Chevrolet used two letters to code the type, size, and horsepower rating of the engine and the transmission type to be used with that engine.

The final vehicle assembly plant sometimes stamped a VIN derivative on the same machined area as the engine ID code. This stamping wasn't mandated until the 1968 model year but has been found (and not found) on 1967 models. If yours has the VIN derivative (and hasn't obviously been restamped), you can be sure the engine is original to your Chevelle. The VIN derivative might look like "T0601ED   7A123456" stamped into the pad on the front passenger side of the block. In this example, 7A123456 decodes to 1967 model year, Atlanta final assembly, and the serial number of the VIN. Sometimes the VIN derivative was stamped into a different area of the block on the flange edge of the rear of the block, near the bell housing mating surface. Sometimes the stamping is found above the timing cover mating surface on the front of the block.

While NOT a hard and fast rule, it has been found that mainly the higher horsepower engines such as the 327/325 RPO L79 and all SS396 engines have a VIN derivative stamping. This VIN derivative stamping is usually found on the engine ID pad located on the block in front of passenger side head such as this example.

File Photo
Tonawanda ~ June 9 ~ 396/325hp w/manual transmission
Note VIN derivative stamped at Kansas City final assembly plant.

 Mandatory VIN stamping of all engines was not required by federal law until the 1968 model year.