1968 Engines

Engines - 1968

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	C.C.S.
EL	396-4	350-L34	Powerglide	A.I.R.
ET	396-4	325-L35	TH-400	C.C.S.
EU	396-4	350-L34	TH-400	A.I.R.

A total of 82,845 6-cyl engines were installed; 39,762 230cid and 43,083 250cid engines.
A total of 381,824 8-cyl engines were installed; 245,032 307cid, 74,007 327cid, and 62,785 396cid 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. To date, all L6 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. See A.I.R. vs. C.C.S.

* 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 1 Fremont Malibu, and one Atlanta Malibu. The EE engine number was changed to EC due to a Powerglide cooler line clip being added to the pan rail.

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.

All 1968 396 engines came with flash-chromed rocker arm covers, oil caps/breathers, and air cleaner lid. The RPO L79 327 cid/325hp engine was also equipped with flash-chromed rocker arm covers, oil filler tube & cap, and open element air cleaner lid.

1968 396 V8 Engine Production

The base engine for the SS 396 series for 1968 was the L35 396cid 325hp engine. There were 62,785 SS 396 sport coupes (55,309), convertibles (2,286), and El Caminos (5,190) sold. There is no way to know how many of the base L35 engines were sold in SS 396 sport coupes, convertibles, or El Caminos.

While there are a know number of SS 396 body styles, just what engines went into a particular body style is not known - at least the numbers have never come to light.

The TH-400 automatic transmission continued to be offered in the SS 396 series and this transmission could only be ordered if a 396 engine was ordered. The base 325hp and optional RPO L34 350hp 396 engines could be ordered with the 2-speed Powerglide but the RPO L78 375hp engine could not.

All L35 and L34 engines were equipped with a Rochester (or Carter equivalent) Quadrajet carburetor; only the L78 engine was still equipped with a Holley carburetor.

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

Note that beginning in 1968 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.

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RPO L35 325 hp 396 with either automatic transmission used the Controlled Combustion System (C.C.S.) emission equipment

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RPO L35 325 hp 396 with either manual transmission used the Air Injection Reactor (A.I.R.) emission equipment

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RPO L34 350 hp 396 engines with any transmission used the Air Injection Reactor (A.I.R.) emission equipment

Small Block V8 Engine

Atlanta

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T0209EC ~ Tonawanda Engine Plant - February 9 - 327/275hp Powerglide - Atlanta assembly plant. The EC engine code suffix was changed from EE due to a Powerglide cooler line clip being added to the pan rail.
Photo Courtesy Vincent Polito

Baltimore

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T0706EI ~ Tonawanda Engine Plant ~ July 6 - 327/250hp Powerglide - Baltimore assembly plant. Note difference in the location of the Tonawanda engine stamp and the associated assembly plant VIN derivative between the 396 engine and the 327 engine shown here. It is also been found fairly common that Baltimore often stamped the letter "B" for the number "8" in 1968, 1BB225759 instead of 18B225759.

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T0907DE ~ Tonawanda Engine Plant - September 07 - 307/200hp Powerglide transmission

Kansas City

Fremont

Big Block Engine

Atlanta

Baltimore

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T0520EF ~ Tonawanda Engine Plant - May 20 - 396/350hp manual transmission (note stamp of 1BB instead of 18B, not uncommon for Baltimore)