The engine identification code consists of the engine assembly plant, the engine assembly date, and a 2 or 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, distributor, and exhaust manifolds were not installed at the engine assembly plant but rather at the final assembly plant.

T = Tonawanda Engine Plant
1111 = November 11
EKH = 396/325 L35, Powerglide transmission, Holley carburetor

Engine Assembly Plant - 1st letter

Code Assembly Plant
F Flint, Michigan
*T *Tonawanda, New York
Assembly Month - 1st and 2nd numbers
Number Month Number Month
01 January 02 February
03 March 04 April
05 May 06 June
07 July 08 August
09 September 10 October
*11 *November 12 December

Assembly Day - 3rd and 4th numbers




Code Size HP  
AA 194-1 120 Manual-3 Overdrive
AC 194-1 120 Manual-3 Heavy Duty Clutch
AG 194-1 120 Manual-3 A.C.
AH 194-1 120 Manual-3 Heavy Duty Clutch/A.C.
AL 194-1 120 Powerglide  
AS 194-1 120 Manual-3 Overdrive/A.I.R.
AT 194-1 120 Manual-3 A.C./A.I.R.
230 ↓        
BL 230-1 140-L26 Powerglide A.I.R.
BM 230-1 140-L26 Powerglide A.C./A.I.R.
BM 230-1 140-L26 Manual-3 Overdrive/A.I.R.
BO 230-1 140-L26 Manual-3 A.C./A.I.R.
CA 230-1 140-L26 Manual-3 Overdrive
CB 230-1 140-L26 Manual-3 A.C.
CC 230-1 140-L26 Powerglide  
CD 230-1 140-L26 Powerglide A.C.
283 ↓        
DA 283-2 195 Manual-3  
DB 283-2 195 Manual-4  
DE* 283-2 195 Powerglide  
DG 283-4 220-L77 Manual-3/4  
DH 238-4 220-L77 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.
DL 283-4 220-L77 Manual-3/4 A.I.R.
DM 283-4 220-L77 Powerglide A.I.R.
327 ↓        
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.
EE 327-4 275-L30 Powerglide  
396 ↓        
ED*** 396-4 325-L35 Manual-3/4  
EF 396-4 360-L34 Manual-3/4  
EG** 396-4 375-L78 Manual-3/4 Holley Carb/Solid Cam
EH 396-4 325-L35 Manual-3/4 A.I.R./Rochester Carb
EJ 396-4 360-L34 Manual-3/4 A.I.R.
*EK*** *396-4 *325-L35 *Powerglide *Holley Carb
EKR 396-4 325-L35 Powerglide Rochester Carb
EL 396-4 360-L34 Powerglide  
EM 396-4 325-L35 Powerglide Rochester Carb/A.I.R.
EN 396-4 360-L34 Powerglide A.I.R.

* Some resources list this engine as DF suffix code. Examples clearly shows DE.
** The L78 engine option was canceled May 11, 1965 and reinstated October 7, 1966.
*** The 396/325 engine occasionally was used with a Holley carburetor and will have the suffix "EDH" or "EKH" with the "H" indicating a Holley carburetor in lieu of the Rochester QuadraJet.

According to accepted production numbers, the 396 engines break down as follows:
2-door sedan pickup L35 325hp base engine - 1,865 (engine standard in both SS396 models)
2-door sedan pickup/coupe/convertible L34 360hp high performance engine - 24,811
2-door sedan pickup/coupe/convertible L78 375hp special high performance engine - 3,099
An estimated 2,965 2-door sedan pickup El Caminos were ordered with one of the 396 engines

Roughly 32.6% of the 325hp 396 was ordered with a Powerglide transmission.
Roughly 67.4% of the 325hp 396 was ordered with a manual transmission.

Roughly 5.8% of the 360hp 396 was ordered with a Powerglide transmission.
Roughly 94.2% of the 360hp 396 was ordered with a manual transmission.

Note the above figures DO NOT mention the El Camino. While the El Camino was NOT available with the SS option the L34, L35, 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.