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1968 Chevelle Engine ID Suffix Codes

 

The engine identification code consists of the engine assembly plant, the engine assembly date, and 3 letter suffix indicating the cubic inch displacement, the horsepower rating, and generally, what type of transmission was to be installed with the engine. Manual transmissions required a bushing in the rear of the bellhousing where an automatic transmission did not. Many engine "accessories" such as the carburetor, alternators, and power steering units were not installed at the engine assembly plant but rather at the final assembly plant.

 

Engine stamp samples

 

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1964

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1965

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1966

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1967

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1968

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1969

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1970

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1971

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1972

 

Engine

Transmission

Notes

Code

Size-Carb

HP-RPO

    
BA 230-1 140 Manual-3 Overdrive
BB 230-1 140 Manual-3 Heavy Duty Clutch/A.C.
BC 230-1 140 Manual-3 Heavy Duty Clutch
BD 230-1 140 Manual-3 A.C.
BF 230-1 140 Powerglide  
BH 230-1 140 Powerglide A.C.
250 ↓        
CM 250-1 155-L22 Manual-3 Overdrive
CN 250-1 155-L22 Manual-3 A.C.
CQ 250-1 155-L22 Powerglide  
CR 250-1 155-L22 Powerglide A.C.
307 ↓        
DA 307-2 200 Manual-3 Overdrive
DB 307-2 200 Manual-4  
DE 307-2 200 Powerglide  
DF 307-2 200 Powerglide  
DN 307-2 200 Manual-3 Heavy Duty Clutch
327 ↓        
EA 327-4 275-L30 Manual-3/4  
EC * 327-4 275-L30 Powerglide Documented on KC-built 13680 & 13637
Documented on Fremont-built 13637
Documented on Atlanta-built 13637
EE 327-4 275-L30 Powerglide  
EH 327-4 250-L73 Manual-3/4  
EI 327-4 250-L73 Powerglide  
EJ 327-4 250-L73 Manual-3 Heavy Duty Clutch/L73
EO 327-4 275-L30 Manual-3 Heavy Duty Clutch
EP 327-4 325-L79 Manual-3/4 Spcl High Perf
ES 327-4 325-L79 Manual-3/4 Spcl High Perf/Heavy Duty Clutch
396 ↓        
ED 396-4 325-L35 Manual-3/4 A.I.R.
EF 396-4 350-L34 Manual-3/4 A.I.R.
EG 396-4 375-L78 Manual-3/4 A.I.R./Spcl High Perf
EK 396-4 325-L35 Powerglide  
EL 396-4 350-L34 Powerglide A.I.R.
ET 396-4 325-L35 TH-400  
EU 396-4 350-L34 TH-400 A.I.R.

 

A total of 82,845 6-cyl engines were installed; 39,762 230-cid and 43,083 250-cid engines.
A total of 381,824 8-cyl engines were installed; 245,032 307-cid, 74,007 327-cid, and 62,785 396-cid engines.

 

The engine assembly date and ID suffix code as well as the partial VIN for all V8 engines is always stamped on the engine pad as shown here. I6 engines were stamped on a pad by the distributor.

 

All 350hp and 375hp, regardless of transmission, as well as 325hp manual transmission SS 396 Chevelles, came equipped with A.I.R.; the 325hp SS 396 with an automatic did not have the A.I.R. system.

 

* EC engine code found on several KC-built 13680 El Caminos like the late January El Camino on the Chassis Broadcast Copy sheet and Malibu engine stamp shown here, at least one Fremont Malibu, and one Atlanta Malibu. The EE engine code was changed to EC due to a Powerglide cooler line clip being added to the pan rail.

 

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When the base 325hp 396cid engine was ordered with an automatic transmission it would have the Closed Combustion System (CCS) instead of the Air Induction Reactor emission system.

 

So, if you have a documented 1968 327/275 w/Powerglide and an EC engine code, let me know the plant and VIN sequence so I can document it here and maybe solve issues for others.

 

1968 396 V8 Engine Production

 

RPO hp Transmission Suffix Production Notes
L35 325 Manual ED 26,831
L35/M35 325 Powerglide EK 02,042  
L35/M40 325 TH-400 ET 19,114  
        46,987 Total L35 Engines
        45,553 Total L35 Chevelles
97% of total L35 engine production went into Chevelles in 1968. 01,434 Service Engines
           
L34 350 Manual EF 9,630  
L34/M35 350 Powerglide EL 0,126  
L34/M40 350 TH-400 EU 3,795  
        13,551 Total L34 Engines
        12,481 Total L34 Chevelles
92.1% of total L34 engine production went into Chevelles in 1968. 1,070 Service Engines
           
L78 375 Manual EG 4,848 Total L78 Engines
        4,751 Total L78 Chevelles
98% of total L78 engine production went into Chevelles in 1968. 0,097 Service Engines
           

 

Beginning with the 1968 model year all engines, not just 396-cid engines, received partial VIN identifying stamps as directed by GM.  Also note difference in the location of the Tonawanda or Flint engine stamp and the associated assembly plant VIN derivative between the 396 engine and the 307/327 engines.

 

Examples of engine assembly plant ID stamped codes and engine VIN derivative stampings.