1972 Chevelle Engine ID Codes - Engine Pad
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, distributor, and exhaust manifolds were not installed at the engine assembly plant but rather at the final assembly plant.
|CAH||250-1||110||Manual-3||Low Compression Engine|
|CTA||402-4||240-LS3||Manual-4||A.I.R., Police, Taxi|
|CTJ||402-4||240-LS3||TH-400||A.I.R., Police, Taxi|
Engine production totals are listed for U.S. production only.
(1) CLA, CLB, and CLS engine codes are shown in numerous publications but there is an ongoing debate if a 402 engine without A.I.R. was ever installed in a 1972 Chevelle regardless of final assembly plant. If anyone has documented proof such as a build sheet showing either CLA, CLB, or CLS engine codes, and NOT SHOWING RPO K19, please contact me via the Contact page.
Those noted with "Police" and/or "Taxi" does not mean these engines were used exclusively in police vehicles or taxi cabs. It simply indicates they were used in those vehicles along with normal, civilian passenger cars.
GM's own 'Restoration Kit' only shows CLA & CLB but do not mention
anything about A.I.R. However, all 1972 Chevelle build sheets
I have code the LS3 as either TA or TB.
** Monte Carlo exclusive
NB2 - California required equipment includes AIR and camshaft with longer valve overlap.
A total of 21,779 6-cyl engines were reported installed
A total of 562,604 8-cyl engines were installed in Chevelles and Monte Carlos; 165,706 307cid, 373,268 350cid, and 23,630 402/454cid engines. However, this does not match the total of 8-cyl cars reportedly built in the U.S. of 578,052. This is a difference of 15,488 8-cyl units with no engines.
Engines reported for the (U.S.-built) Monte Carlo (163,087) does not match the production figure of 163,085 cars. Those break down to 151,859 350cid, 9,960 402cid and 1,268 454cid engines. Seems to be 2 extra engines reported.
Chevrolet reports 584,532 transmissions on the Accumulative Production Report of July 31, 1972. This number is only for U.S.-built Chevelles. This figure does not match the total reported U.S.-built Chevelles of 584,530. This is a difference of 2 transmissions (all types) without cars to put them in. The listed transmissions for the (U.S.-built) Monte Carlo does match the 163,087 engine production but not reported model production number of 163,085.
There is some breakdown of engines or transmissions imported from
Canada. Hopefully there will be more as more information becomes available.
From Vintage Vehicle Services documentation it is known:
* Of the 21,106 Malibu sport coupes imported into the U.S. 1,542 were equipped with RPO Z15, 266 of those were equipped with RPO LS5, 149 were equipped with the M22 H.D. 4-speed (leaving the remaining 117 equipped with the M40 Turbo Hydramatic 400).
* * Of the 21,106 Malibu sport coupes imported into the U.S. 1,542 were equipped with RPO Z15, 520 of those were equipped with RPO LS3, 807 were equipped with the M20, and 226 equipped with ZL2.
* Of 8,083 Malibu sport coupes built in Canada for Canada sales, 152 were equipped with the LS5 engine option.
* Of 520 Malibu sport coupes with the Z15 option were built with the LS3 engine.
Engine Date/Suffix Code Stamp
T0924CM - Tonawanda Engine Plant, Septermber 24 (1971), CM(A), 307-2, TH350. Note the "A" in the suffix code does not appear to have been stamped.