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
0114 = January 14
TW = 402/350 L34 w/TH400 (Note on this Atlanta P-O-P the engine is coded with the two letter suffix TW.)

⁽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. 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 another source, Chevelle, Malibu & El Camino ID numbers 1964-87 shows the CRN code for a manual/4-speed.  Every Chevelle LS5 build sheet I have shows RT for an LS5 w/manual transmission and RQ for an LS5 w/TH400.  A Monte Carlo LS5 build sheet shows RN for an LS5 w/TH400.  I'll take the information on a build sheet over other published data.