B/RB Block Identification

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Year Identification Stampings

For 1960-1964 blocks the engine code will start with a letter year code in the set [P R S T V] that indicates [1960 .. 1964] (in set order). The Year code is followed by the first two digits of the CID displacement (ex.36,38,41,42 would indicate 361,383,413,426). If an additional three digits follow, usually after a dash, these will indicate the date it was stamped (not necessarily cast).

For Engines made begining in 1965, again the first character indicates the year [A B C D E F G H J] for [1965 .. 1967] (in set order). The full CID displacment will follow. If a dash and three numbers follow, this indicates the date it was stamped (not necessarily cast). Some of these engines will be stamped with an HP indicating that it was destined for a high performance application. Likewise, a L or LC would indicate a low compression engine. This isn't an either/or relationship. A block might not have either an HP or an LC. And not all block that wound up in high performance applications always got a block stamped HP.

For Engines made begining in 1974, the CID displacement will be prepended a "[4..8]T-" Where 4T- means 1974, and 8T- mean 1978. The "T" indicates that it was made at the Trenton Plant (it does not mean truck). Quite often, these stamped IDs will be followed with an E indicating a cast crank.

Oversize/Undersize Stampings

There are many other stmapings that wound up on the ID pad or along the oil pan rail. These were mostly to indicate to the engine assemblers that oversize or undersize components will need to be used because a journal or bearing was machined to require it. Here is a short list:

Symbol	Descriptions
M	.001 undersize main bearing journals
A	.020 oversize cylinder bores
E	cast cranks
Diamond	oversize tappets
O.S.	.005 oversize valve stems
P	premium fuel
R	regular fuel
Maltese Cross	.001" undersized bearing shells
Maltese Cross and X	.010" undersized crankshaft
RX or MX	all main or rod journals .010" undersized
S	special engine
WT or TW	water test
X	oversized valve guides

Casting Numbers and Markings

Below is a listing of casting numbers for A-series, B/RB-series, LA-series, and G/RG-series engines

For additional engine ID information for B/RB engines,see this page.

 Mopar Engine Block Casting Numbers 

casting number	CID	years	notes
1737629	361	1961-1964
1851729	383	1959-1964
1852029	413	1959-1962	Truck
1852029	413	1962	Max Wedge
1944929	350	1958
2120329	383	1959-1964
2120529	413	1959-1965
2202843	170	1960-1964	(G-series)
2202857	225		(RG-series)
2205528	225		(RG-series)
2205630	170		(G-series)
2205697	413	1959-1965
2205697	426	1964
2205712	361	1958-1966
2264230	318	1960-1966	(A-series)
2264478	170		(G-series)
2406730	426	1963-1965
2432230	426	1964-1965
2463230	170	1965	(G-series)
2463395	170	1965	(G-series)
2463430	225	1960-1967	(RG-series)
2465330	273	1964-1966	(LA-series)
2468030	413
2468130	383	1959-1971
2468330	426	1964-1971	Hemi
2532230	426	1964-1666
2536030	318	1967-1975	(LA-series)
2536130	273	1965	(LA-series)
2536430	440	1966-1972
2536430	440	1966-1972
2568130	383	1959-1971
2658836	426	1966-later	Industrial
2780930	340	1968-73	(LA-series)
2806130	273	1966-69	(LA-series)
2806830	225	1968-1970	also 198(RG-series)
2951694	225		(RG-series)
3418496	360	1971-74	(LA-series)
3462605	225	1975	(RG-series)
3577130	340	1970	T/A(LA-series)
3614230	400	1971	(thicker main webbing)
3698330	440	1973-1978
3698630	400	1973-1978
3698830	440	1973-1978
3870230	360	1975	(LA-series)
4006530	400	1976-1978
4006530	440	1974-1978	(??)
4006630	440	1975-1978
4006730	318	1976-1979	(LA-series)
4006830	360	1976-1980	(LA-series)
4027163	318	1980-1985	(LA-series)
4027593	318	1980-1985	(LA-series)
4027596	360	1980-1985	(LA-series)
4041314	225	1976-1977	forged crank(RG-series)
4071051	360	1980-1985	(LA-series)
4071072	225	1976-1977	cast crank(RG-series)
4104230	318	1980-1983	(LA-series)
4323302	318	1986-1990	(LA-series)
4323345	360	1986-1989	(LA-series)
4343475	360	1986-1988	(LA-series)
4343923	360	1986-1988	(LA-series)
4448308	360	1989-1991	(LA-series)

 

See Dutra's SlantSix.org article on blocks to really gain an understanding of the casting process

See Muscle Mopar's write up for more information