ENGINE IDENTIFICATION

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

CodeAssembly Plant
FFlint, Michigan
*T*Tonawanda, New York
  
Assembly Month - 1st and 2nd numbers
NumberMonthNumberMonth
01January02February
03March04April
05May06June
07July08August
09September10October
*11*November12December

Assembly Day - 3rd and 4th numbers
01...31

Engine

Transmission

Notes

CodeSizeHP 
AA194-1120Manual-3Overdrive
AC194-1120Manual-3Heavy Duty Clutch
AG194-1120Manual-3A.C.
AH194-1120Manual-3Heavy Duty Clutch/A.C.
AL194-1120Powerglide 
AS194-1120Manual-3Overdrive/A.I.R.
AT194-1120Manual-3A.C./A.I.R.
230 ↓    
BL230-1140-L26PowerglideA.I.R.
BM230-1140-L26PowerglideA.C./A.I.R.
BM230-1140-L26Manual-3Overdrive/A.I.R.
BO230-1140-L26Manual-3A.C./A.I.R.
CA230-1140-L26Manual-3Overdrive
CB230-1140-L26Manual-3A.C.
CC230-1140-L26Powerglide 
CD230-1140-L26PowerglideA.C.
283 ↓    
DA283-2195Manual-3 
DB283-2195Manual-4 
DE*283-2195Powerglide 
DG283-4220-L77Manual-3/4 
DH238-4220-L77Powerglide 
DI283-2195Manual-3Overdrive/A.I.R.
DJ283-2195PowerglideA.I.R.
DK283-2195Manual-4A.I.R.
DL283-4220-L77Manual-3/4A.I.R.
DM283-4220-L77PowerglideA.I.R.
327 ↓    
EA327-4275-L30Manual-3/4 
EB327-4275-L30Manual-3/4A.I.R.
EC327-4275-L30PowerglideA.I.R.
EE327-4275-L30Powerglide 
396 ↓    
ED***396-4325-L35Manual-3/4 
EF396-4360-L34Manual-3/4 
EG**396-4375-L78Manual-3/4Holley Carb/Solid Cam
EH396-4325-L35Manual-3/4A.I.R./Rochester Carb
EJ396-4360-L34Manual-3/4A.I.R.
*EK****396-4*325-L35*Powerglide*Holley Carb
EKR396-4325-L35PowerglideRochester Carb
EL396-4360-L34Powerglide 
EM396-4325-L35PowerglideRochester Carb/A.I.R.
EN396-4360-L34PowerglideA.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.