Chevelle V8 Cylinder Head Casting Numbers - 1964 through 1972

These head castings were used in various other models of the Chevrolet lineup such as the passenger car, Chevy II/Nova, Camaro and Corvette. Only Chevelle-specific information is listed here to conserve space. Some casting numbers are NOT listed as they may have been used in other models of the Chevrolet lineup but were NOT used in the Chevelle - such as the 1965 409cid heads #3830817 & #3852583 or 67 Camaro heads #3876775.

The casting number is probably the most significant feature on a cylinder head as it's the hardest to alter. The casting date is usually found near the casting number. Both are found under the valve cover be it a small block V8 (283/307/327/350) or big block Mark IV V8 (396/402/454).

It's important to remember the 'to' and 'from' dates listed may vary due to production lead time and stock inventories being depleted. For example just because a particular head casting may be listed as being used from January to April doesn't imply that the engine assembly plants discarded all pre-January heads or on the 1st of May discard all heads they had in inventory to begin using the newer design.

Casting clocks. Note the 11 dots plus the number 0 indicating the particular hour of a shift the heads were cast.

Cylinder heads are normally date coded in the form of a letter for the month (see table below), two numbers for the day and a single number for the year.  For example, C259 indicates a date of March 25, 1969.

V8 Cylinder Head Casting Month Codes
A - January	B - February	C - March	D - April
E - May	F - June	G - July	H - August
I - September	J - October	K - November	L - December

Caveats to production dates. Due to inventories, shipping schedules, etc. it is entirely possible that cylinder heads being phased out of production may still appear on Chevelles built after that time.

Head Number	Year	Engine	Horsepower	Valve Size Int./Exh.	Combustion Chamber cc.	Notes
3795896	1964	283 327	195, 220 250	1.72/1.50	59.669	Used in 1964 and 1965.
3782461	1964 1965 1966	327 327 327	300 250, 300 275	1.94/1.50	62.076	Production ended approximately June of 1966 and replaced with #3890462. Casting symbol on exterior face of head is the infamous double-hump design.
	1964 1965 1966	327 327 327	350 350 350	2.02/1.60	62.076	1966 is late March introduction.
3795896	1965	283	195, 220	1.72/1.50	59.669	Casting symbol on exterior face of head is single centered pyramid on square block.
3856208	1965	396	375	2.19/1.75	108.989	First square-port Mark IV head. Has spark plug shield boss.
3872702	1966	396	325, 360	2.06/1.72	98.427	All oval-port applications. Has spark plug shield boss. It is debatable as to whether these plug shields were used on the Chevelle but the shields listed in Chevrolet parts books included the Chevelle application.
3873858	1966	396	375	2.19/1.72	108.989	All high performance square-port engine applications. Has spark plug shield boss.
3884520	1966 1967	283 283	195, 220 195	1.72/1.50	60.530
3890462	1966 1967 1966 1967	327 327 327 327	275 275 350 325	1.94/1.50 1.94/1.50 2.02/1.60 2.02/1.60	62.076 63.305 62.076 63.305	Similar to 3782461. Used from January 1966 through May 1967.
3904390	1967	396	325, 350	2.06/1.72	98.427	First head without spark plug shield boss. Used until January when replaced with #3909802.
3904391	1967	396	375	2.19/1.72	106.8	Used at least through May 1967 when replaced with #3919840.
3909802	1967	396	325, 350	2.06/1.72	100.967	January through April of 1967, with redesigned combustion chamber. June 1967 casting dates have been reported for this head.
3911032	1968	307	200	1.72/1.50	69.629	Used in 1968 only. Has temperature sending unit boss.
3917215	1967 1968	396	325, 350	2.06/1.72	100.967	First Mark IV oval-port with temperature sending unit boss, otherwise identical to #3909802. Production from May 1967 to May 1968.
3917291	1967 1968	327	275	1.94/1.50	63.305	Used in late 1967 (May/April) and all 1968. Identical to #3890462 except it has the temperature sending boss. The late 1967 unit has the temperature sending unit boss but is not tapped.
3917291	1967 1968	327	325	2.02/1.60	63.995	Combustion chamber enlarged and valve guide boss diameter increased to accept the 2.02/1.60 valves.
3917293	1968	327	250	1.72/1.50	75.340	Low compression, identical to #3884520 except for combustion chamber change and addition of temperature sending boss.
3919840	1967 1968 1969	396	375	2.19/1.72	106.8	First Mark IV to have temperature sending boss. The late 1967 unit has the temperature sending unit boss but is not tapped. Identical to #3904391 except for temperature sending unit boss and two accessory bolt holes added.
3919842	1969	396	375 (L89)	2.19/1.84	106.8	Aluminum head with temperature sending unit boss, two accessory holes drilled and tapped, revised exhaust manifold surface. Two versions were used during 1968 (non-Chevelle) and 1969. The 1968 and early 1969 version had plugs in both ends of the cylinder head. Approximately June of 1969 one plug was eliminated.
3927185	1969 1970	307	200	1.72/1.50	69.625	Identical to #3884520 except has temperature sending unit boss. Three accessory bolt holes added to each end of the head and combustion chamber revised.
3927186	1969 1970	350	300	1.94/1.50	63.305	Similar to #3917291 & #3782461, but with temperature sending unit boss, three accessory holes and casting symbol was smaller.
3931063	1969	396	325, 350	2.06/1.72	100.967	Similar to #3909802 & 3917215 with two accessory bosses above #3 (or #6) exhaust ports for air conditioning rear support bracket. Straight casting flashing.
3932441	1969 1970	350	250, 255 250	1.94/1.50	76.26	Similar to #3927186 with redesigned combustion chamber.
3947041	1969 1970	350	300	1.94/1.50	63.305	Similar to #3782461 with redesigned combustion chamber, addition of a temperature sending unit boss and three accessory holes on end.
3964290	1969 1970 1970	396 402 454	325, 350 330, 350 360	2.06/1.72	100.967	Similar to #3931063 with spark plug seat changed to tapered, "peanut" plug but early castings had standard, "N" reach plug. Straight casting flashing.
3964291	1969 1970	396 427 402 454	375 425 375 450	2.19/1.88	109.037	Similar to #3919840 with spark plug seat changed to tapered, "peanut" plug but early castings had standard, "N" reach plug. Last closed chamber cast iron square-port head. Produced in both plug designs for service replacement of 1965 through 1969 applications.
3973487	1971 1972	350 350	245, 270 165, 175	1.94/1.50	75.47	Similar to #3832441 & #3782461 with redesigned combustion chamber, addition of temperature sending unit boss, three accessory bolt holes added to end of head, tapered spark plug seat and different external identification symbol cast near the internal casting number.
3973487X	1972	350	165, 175	1.94/1.50	75.47	Used only in late 1972 and overlapped production with #3998993.
3986339	1971	307	200	1.72/1.50	74.56	Similar to #3884520 with redesigned combustion chamber, temperature sending unit boss and tapered spark plug seat.
3993820	1971	402 454	300 365	2.06/1.75	113.060	Cast iron, oval-port and similar to #3931063 with change to open-chamber design, redesigned intake and exhaust valve seats, and tapered spark plugs.
3994026	1971	454	425	2.19/1.88	118.000	Cast iron, square-port with tapered spark plug. Last Mark IV square-port with open chamber design.
3998991	1972	307	130	1.72/1.50	74.56	Similar to #3795896 with tapered spark plug, redesigned combustion chamber, and temperature sending unit boss. First head to use hardened valve seats for unleaded fuel.
3998993	1972 1973 1973	350 307 350	165, 175 115 145, 175	1.94/1.50	75.47	Introduced mid-year (January) to replace #3973487X.
3999241	1972	402 454	240 270	2.06/1.72	113.06	Similar to #3993820 with tapered spark plug seat.
353049	1973	454	245*	2.06/1.72	113.06	Used for all 1973 454 applications.
333882	1974-75 1974 1975	350 400 400	All 150, 180 175	1.94/1.50	75.47	Similar to #3998993 with tapered spark plug seat.
336781	1974 1975	454 454	235 215	2.06/1.72	113.06	Used for all 1974 and early 1975. Replace by #346236 mid-year 1975.
346236	1975	454	215	2.06/1.72	113.06	Replaced #336781 mid-year 1975.

* The 1973 454 Corvette engine was rated at 270hp. Since this head has the same intake/exhaust and cc volume, it's not known why it is listed at 245hp for 1973.

1966 Oval port head; notice tapped bosses for spark plug shields.

The top head is the 'lower horsepower' version (300hp and under) used on 67-68 327 applications with 1.94 intake and 1.50 exhaust while the bottom head is the performance version (325hp and higher) used on 67-68 327 applications with 2.02 intake and 1.74 exhaust. These happen to be casting #3917291 with 63.305 and 63.995 cc combustion chambers respectively.  Other 'pairs' of 327 heads 1.94 vs. 2.02 intake valve size and different combustion chamber sizes are found in other years with casting numbers 3782461 (64-66 model years) and 3890462 (66-67 model years).