1970 Engines

Engines - 1970

Engine pad stamps - 402/454 production numbers

The engine identification code consists of the engine assembly plant, the engine assembly date, and a 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.

The "396" engine for 1970 was actually 402 cubic inches. The L34 and L78 versions of this engine for the SS 396 were actually 402 cubic inches while the non-SS 396 LS3 engine was labeled as a 400 Turbo-Jet V8 or 400-4bbl engine and was rated at 330 horsepower. This "400" engine should not be confused with the RPO LF6 400 cubic inch Turbo-Fire V8 only available in the Monte Carlo and full size Chevrolets in 1970; this was often referred to in tune up manuals as a 400-2bbl engine.

Engine			Transmission	Notes
Code	Size-Carb	HP-RPO
CRF	250-1	155	Manual-3
CCG	250-1	155	Powerglide
CCK	250-1	155	TH-350	Taxi, Police
CCL	250-1	155	Manual-3	Taxi, Police
CCM	250-1	155	Powerglide	Taxi, Police
307 ↓
CNC	307-2	200	Manual-3/4
CND	307-2	200	Manual-4
CNE	307-2	200	Powerglide
CNF	307-2	200	TH-350
CNG	307-2	200	Manual-3	Low Compression Engine
CNH	307-2	200	Powerglide	Low Compression Engine
350 ↓
CNI	350-2	250-L65	Manual-3/4
CNJ	350-4	300-L48	Manual-4
CNK	350-4	300-L48	Powerglide
CNM	350-2	250-L65	Powerglide
CNN	350-2	250-L65	TH-350
CRE	350-4	300-L48	TH-350
400 ↓
CRH *	400-2	265-LF6	TH-350	Monte Carlo
CZX *	400-2	265-LF6	Manual	Monte Carlo
402 ↓
CGR	402-4	330-LS3	Manual-4	Found on Vintage Vehicle Services Report
CKN	402-4	330-LS3	TH-400
CKO	402-4	375-L78	Manual-4
CKP	402-4	375-L78 (w/L89)	TH-400	Aluminum Heads
CKQ	402-4	375-L78	Manual-4	Heavy Duty Clutch
CKR	402-4	330-LS3	Manual-4
CKS	402-4	330-LS3	Manual-4	Heavy Duty Clutch/LS3
CKT	402-4	375-L78 (w/L89)	Manual-4	Aluminum Heads
CKU	402-4	375-L78 (w/L89)	Manual-4	Heavy Duty Clutch/Aluminum Heads
CTW	402-4	350-L34	TH-400
CTX	402-4	350-L34	Manual-4
CTY	402-4	375-L78	TH-400
CTZ	402-4	350-L34	Manual-4	Heavy Duty Clutch
454 ↓
CRN * ⁽²⁾	454-4	360-LS5	TH-400	Monte Carlo
CRQ	454-4	360-LS5	TH-400
CRR	454-4	450-LS6	TH-400
CRS ⁽¹⁾	454-4	450-LS6(w/L89)	TH-400	Aluminum Heads
CRT	454-4	360-LS5	Manual-M22
CRU	454-4	360-LS5	Manual-M22	Heavy Duty Clutch
CRV	454-4	450-LS6	Manual-M22
CRX	454-4	450-LS6	Manual-M22	Heavy Duty Clutch
CRY ⁽¹⁾	454-4	450-LS6(w/L89)	Manual-M22	Aluminum Heads/Heavy Duty Clutch

Notes:

⁽¹⁾ There is some discussion about the 454 being sold with 454 engines and aluminum heads. One very respected source says that according to records at Tonawanda no 454 with aluminum heads were assembled. Their records indicate the L89 option was cancelled (not replaced) with the demise of the L78/L89 combination. On the other hand, some have reported seeing the CRS code on engine blocks and one registrant here has a dealer bill-of-sale plus the warranty Protect-O-Plate card both showing the CRY code.

⁽²⁾ One source, Chevrolet by the numbers, shows CRN for a 1970 Monte Carlo 454/360 with TH400 where a second source, Chevelle, Malibu & El Camino ID numbers 1964-87 (as well as many websites) shows the CRN code for a manual/4-speed Chevelle, and finally Chevelle and El Camino ID Model Codes (NCOA purple book) does not show this engine code at all probably due to the fact it is a Monte Carlo only engine. Every Chevelle LS5 build sheet I have shows RT for an LS5 w/manual transmission (26 to date) and RQ for an LS5 w/TH400 (another 26). Four Monte Carlo LS5 build sheets shows RN for an LS5 w/TH400. I'll take the information on a build sheet over other published data.

These figures are for the U.S. production of Chevelles only (unless otherwise indicated) and does not include the Monte Carlo.
A total of 39,207 6-cyl engines were installed; 29,791 in U.S. built Chevelles and 10,416 imported from Canada.
A total of 413,255 8-cyl engines were installed; 198,285 307cid, 150,745 350cid, and 64,225 402/454cid engines.

* Monte Carlo exclusive

CGR engine suffix has been noted on a Canadian-built LS3 Chevelle with manual transmission.
CRF engine suffix has been noted on a Canadian-built L34 Chevelle with manual transmission.

How this 64,225 figure of combined 402/454 engines was arrived at is not known. Given the number of Z25 and Z15 options (including optional L78 and LS6 engines), the total arrived at is 63,372 for SS optioned Chevelles but this total includes the two SS options both exported to and imported from Canada so the exact U.S. figures are difficult to ascertain.

Vintage Vehicle Services documents indicate that of 10,176 Malibu Sport Coupes built in Canada for sale in Canada, 700 were equipped with the L34 engine.

Vintage Vehicle Services documents indicate that 3,306 Z25 optioned Malibu Sport Coupes with 1,750 ZL2 hoods along with 299 Z15 (LS5 only) optioned Chevelle Sport Coupes were exported for sale to the U.S.

Vintage Vehicle Services documents indicate that of the 25,938 V8 Malibu Sport Coupes built, 992 were ordered with the M20 and 2,152 with the U14 gauge package.

In addition to these imports and exports, a total of 9,338 LS3 engines must be accounted for somewhere in this 64,225 402/454 engine figure.

53,599 - Z25 SS 396 options ordered (51,455 base L34 plus 2,144 optional RPO L78)
8,773 - Z15 SS 454 options ordered (4,298 base LS5 plus 4,475 optional RPO LS6)

Chevrolet only reports 442,046 engines and transmissions on the Accumulative Production Report of August 31, 1970. This number is only for U.S. built Chevelles. There is no breakdown of engines or transmissions imported from Canada.

1970 396/454 Engine Production

The '396' L34 & L78 engines were actually 402 cubic inches in 1970. The L34/L78 & L89 aluminum head option on the L78 figures are for Chevelle ("A" body), Camaro ("F" body), and Nova ("X" body) platforms and are broken down as such.

The LS3 is a 402 cid Mark IV engine listed as a Turbo-Jet 400 and was available on all factory V8 wagons, the standard Chevelle series sport coupe and pickup, and all Malibu series body styles including the Custom El Camino that were NOT SS optioned. The LS3 was not available when the Z25 SS 396 equipment option was ordered. The LS3 was identified with '400' emblems on the front fenders in the same manner as the '350' and '307' emblems.

There are also several suffix code designations that are not shown in the available report from the Tonawanda engine plant and therefore it is assumed the quantity of these engines is included with another such as the L34 engine with Heavy Duty Clutch has a suffix of CTZ which is not shown in the report and any quantities of this engine is incorporated into the CTX suffix coded L34 w/manual transmission. These engine codes with no specifically known numbers will be shown with an asterisk (*) for identification.

L34 figures: The L34 is the base engine for RPO Z25. A total of 53,599 Z25 optioned Chevelles were sold. By subtracting the L78 optional engine and L89 option Chevelle production of 2,162 it leaves a total of 51,437 L34 Chevelles. Tonawanda engine totals are for all Chevelle, Camaro, and Nova series.

LS5 figures: The LS5 is the base engine for RPO Z15. A total of 8,773 Z15 optioned Chevelles were sold. By subtracting the LS6 optional engine production of 4,475 it leaves a total of 4,298 LS5 Z15 optioned Chevelles. Actually fewer base LS5 Z15 Chevelles were sold than the optional LS6 engine.

Engine pad stamps - 402/454 production numbers