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Chevrolet Small Block Heads – Casting Numbers and Specifications

Chevrolet Small Block Heads

Chevrolet Small Block Heads Combustion chamber types

Closed Chamber.

Open Chamber.

Chevrolet Small Block Heads Intake Port Types.

Rectangular Port.

Large Oval Ports.

Small Oval Ports(Peanut Port) Heads.

Choosing a performance head for your Chevrolet Small Block.

Casting Numbers to look For.

Chevrolet Small Block Head Casting Numbers

Casting Number	Year	Engine	Chamber Size	Intake Valve	Exhaust Valve	Notes
176450	75-76	262,305		1.71	1.5
330545	73	307, 350	74	1.72	1.5001	245 or 250 Horsepower
330545	71-75	350	76cc	2.02	1.6
330862	71-73	400		1.94	1.5001
333881	71-76	350		1.72	1.5001	165 or 270 Horsepower
333881	74-75	350	76cc	2.02	1.6
333882	70-80	350,400		1.94	1.5	137.5 CFM Intake and 95.4 CFM Exhaust
340292	73-80		64cc			Angle plug, over the counter
354434	75-80	262, 267, 305	60cc	1.71	1.5
358741	71-79	262,305		1.71	1.5
367450	75-76	262,305		1.72	1.3
376445	77-85	350	76cc	1.72	1.5001	Truck
376450	75-81	262, 267, 305	60cc			6 or 7 exhaust bolt holes
376495	69-79	350
383882	71-73	400
399380	70-73	400
426424	72-82	305,350,400
458624	69-84	350				Truck
458642	75-84	350
460703	78-80	350
462614	77-79	305, 350	60cc
462624	75-87	350		1.94	1.5	Z-28 Camaro
462624	78-81	305		1.94 0R 2.02	1.6
462624	79-85	400	76cc	1.94	1.5
468642	75-84	350, 400		1.72	1.5001
471513	79-81	267, 350
472424	76-79	305
517513	79-82	267, 350
1816887	63	283				Made in “Canada” GMC Truck
3238882	68-69	350
3297185	57-67	327		1.72	1.5001
3297185	63-67	307,237,350
3636839	55	265		1.72	1.5
3636839	59	265
3703523	55	265		1.72	1.5001
3713358	55-56	265		1.72	1.5	Truck
3713569	55-56	265		1.72	1.5	Truck
3714482	62-67	327		1.72	1.5
3725306	56-57	265		1.72	1.5	Corvette
3727185	69-73	307		1.72	1.5001
3731262	56	265		1.72	1.5	Corvette 2 X 4 Barrel
3731539	57	283		1.72	1.5	283 HP FI
3731539	57-66	283
3731544	57-61	265,283		1.72	1.5
3731554	55-66	265,283		1.72	1.5	2 Barrel
3731556	57	283		1.72	1.5	Made in “Canada” Truck
3731762	56	265		1.72	1.5001	Corvette 2 X 4 Barrel
3737465	60-61	283		1.72	1.5
3737775	62-67	283, 327		1.72	1.5
3740997	57	283		1.72	1.5
3743056	58	283		1.72	1.5	Truck
3743096	62-67	327		1.72	1.5	GMC Truck
3747363	57	265		1.72	1.5
3747363	57-62	283
3747363	58-61	327				Truck
3747460	59-67	283, 327	70cc
3748056	62-67	327		1.72	1.5001
3748720	57-58	283			1.5
3748770	58	265
3748770	55-62	283		1.72	1.5
3748772	57-61	283		1.72	1.5
3755537	57-62	283		1.72	1.5	2 Barrel
3755538	59	283		1.72	1.5001	Corvette FI
3755539	58-62	283		1.72	1.5	Truck
3755549	57-62	283		1.72	1.5
3755550	57-62	283		1.72	1.5	Corvette FI
3755585	62-67	327		1.72	1.5	GMC Truck
3760116	59	283		1.72	1.5
3767460	59-64	265,283,327	68	1.72	1.5
3767462	62-67	327		1.94	1.5
3767465	59-61	283		1.72	1.5001
3767754	59-61	283	60cc
3767792	60-67	283		1.72	1.5
3770126	67-70	327, 350		1.94	1.5
3773012	55	265		1.72	1.5001	Corvette
3774634	64-67	327
3774682	60-67	283, 327	70cc	1.72	1.5
3774684	57-67	283,327	75cc	1.72	1.5	Truck
3774690	58	283				Corvette fuel injection
3774692	58-67	283	60cc			Corvette
3776434	64-67	327
3782461	62-67	302,327,350	62cc		1.6	Camel hump, no accessory holes, 160/62cc port volumes
3782461X	67	283, 327	62cc		1.6	Camel hump, no accessory holes, larger 172/64cc port volumes
3782462	62-67	327
3782879	64-67	327		1.94	1.5
3790721	65-67	283		1.72	1.5
3792563	58-72	327		1.72	1.5
3795893	62-64	283,307,327
3795896	63-65	283	60cc
3795896	64-67	283, 327	60cc	1.72	1.5
3796896	63-67	283
3798996	67	327	60cc	1.72	1.5
3814462	60-67	350		1.94	1.5001
3814480	62-67	283, 327	70cc	1.72	1.5	Truck
3814482	59	283, 327	75cc	1.72	1.5001	Truck
3817680	62-67	283, 327		1.72	1.5	Fuel Injection
3817681	66-67	327		1.72	1.5
3817681	61-62	350		1.72	1.5
3817682	55	283		1.72	1.5	2 Barrel
3836839	55-67	265		1.72	1.5
3836842	62-67	283, 327		1.72	1.5
3836924	58-62	283		1.72	1.5001
3836942	58-62	283		1.72	1.5001
3837063	56	283		1.72	1.5001
3837064	55-62	265, 283		1.72	1.5
3837065	57	265		1.72	1.5	Truck
3837739	62-67	283		1.72	1.5
3837775	57-58	283,327		1.72	1.5001
3848720	65	283		1.72	1.5
3849820	65-67	327		1.72	1.5001
3849935	62-64	283		1.72	1.5
3852174	62-67	327		1.72	1.5
3854520	68-76	283,327		1.72	1.5
3855961	57-60	350		1.72	1.5
3867802	56-57	283		1.72	1.5	Corvette Fuel Injection
3873064	62-67	265		1.72	1.5001
3876132	71-73	327		1.94	1.5
3876487	57-67	350		1.94	1.5001
3876775	60-67	283,327	75cc	1.72	1.5	Truck
3878775	60-67	327				Truck
3884520	62-68	283, 327	60cc	1.72	1.5	Some marked “Made in Canada”, also used by Studebaker
3890462	62-67	302,327,350	64cc	1.94 OR 2.02	1.6	Camel hump, no accessory holes
3891462	64-67	302,327,350		1.94	1.5001
3891492	87-up	327
3901068	68	350	64cc			Crate motor, 285HP
3911011	68	327		1.72	1.5001
3911032	58-70	307, 327	70cc	1.72	1.5	Truck
3912264	63-64	283		1.72	1.5
3912265	68-70	283		1.72	1.5
3912291	65-67	302,327,350		1.94	1.5001
3912311	65-67	327, 350		1.94	1.5
3912313	65-73	327		1.72	1.5
3914636	67	307		1.72	1.5
3917264	67-68	302		2.02	1.6	Z28 Camaro
3917290	68-70	307, 327		1.71	1.5	Truck
3917291	67-69	302, 307, 327, 350	63cc	1.94	1.5	Camel hump, no accessory holes
3917292	67-68	327, 350	64cc	1.94	1.5	Camel hump
3917293	66-69	307, 327	75cc	1.72	1.5
3921175	67-79	327		2.02	1.6
3923441	68-73	307,327,350		1.71	1.5
3927185	69-76	307,327,350	70cc	1.72	1.5
3927186	68-72	302, 327, 350	64cc	2.02	1.6	Camel hump, has accessory holes
3927187	69	302, 350	64cc	2.02	1.6	Camel hump, has accessory holes
3927188	68	307,327,350	74cc	1.72	1.5	Truck
3927188	70	307	74cc
3928454	68	307		1.72	1.5
3928455	68	302,327		2.02	1.6
3928494	68	327,350		2.02	1.6
3928495	68-73	327		1.94	1.5
3931633	68-76	307		1.72	1.5
3931635	68-69	350		1.72	1.5
3931637	68	327		1.94	1.5
3931638	68	327		1.72	1.5	Truck
3931639	68-73	302		2.02	1.6
3932373	67-79	307		1.72	1.5
3932441	68-72	327, 350	76cc	1.94	1.5	152 CFM Intake 93.2 CFM Exhaust
3932441X	68-79	350, 400	80cc
3932454	76	350				Truck
3932454	68-73	307,350		1.72	1.5
3932882	68	400		1.94	1.5
3933148	69	350
3941174	69-70	327
3946812	69-79	350		1.72	1.5	Truck
3946813	68-70	350		1.72	1.5	Truck
3947014	68-70	350
3947040	68-79	327	64cc			Right angle casting identifier,, used in trucks, no accessory holes
3947041	69-71	302, 327, 350	64cc	1.94	1.5	Right angle casting identifier, accessory holes,
3947041X	70-76	302, 350	64cc			Right angle casting identifier, 165cc intake port, accessory holes,
3951598	68-77	400	76cc	1.94	1.5	2 barrel
3961598	70	400
3964286	67-71	350		1.72	1.5
3965742	67-79	350				Over the counter, angle plug L98 style
3970126	69-73	327,350		1.71	1.5	CFM inl 148.3 / exh 87.6
3971293	64-70	307,327
3973195	70	400				Truck
3973370	68-72	350	64cc			Over the counter in US, Canadian 350/300hp production use in Pontiac, straight or angle plug
3973414	68-79	327, 350	64cc	2.02	1.6	Camel Hump, LT1-350/370hp
3973487	71-76	350	75cc	1.94 or 2.02	1.5 or 1.6
3973487X	62-67	350	75cc	1.94 or 2.02	1.5 or 1.6
3973493	67	400		1.94	1.5	CFM inl 143 / exh 87
3973493	71-72	400	76cc	1.94	1.5
3981462	71	327		1.94	1.5
3981462	69-79	302		1.94	1.5
3986316	68-69	350	76cc
3986330	70-76	350
3986336	71	350	76cc
3986336X	68-71	350	76cc
3986339	62-68	307, 350	74cc
3986339	68-76	307		1.72	1.5
3986339	68-79	350		1.72	1.5
3986339X	68-73	307, 350	74cc
3986388	70-71	350		1.71	1.5	Truck
3986388	69-72	307		1.72	1.5
3990462	72	327		1.94	1.5
3991492	72-75	327,350	64cc	2.02	1.6	LT1, Camel hump, accessory holes, straight plug
3997417	68-69	307	72	1.72	1.5001	Cars
3998916	70-76	350 , 400	76cc	1.94	1.5	Also used w/’72 350 LT1, big valve, screw in studs
3998920	68-76	350		1.94	1.5
3998991	71-73	307, 350	75cc	1.72	1.5
3998993	68-76	307, 350	75cc
3998993	78-84	350		1.94	1.5	CFM inl 150 / exh 91
3998997	68-76	305, 350	76cc	1.94	1.5
3998997	72-73	350,400		1.94	1.5
4079261		350
6259425		350		1.72	1.5
6259515		350	76	1.94	1.5001	cars
6260856	87-95	350		1.72	1.5
6272070	87-95	350	76	1.72	1.5001
8917291	87-95	350	64	1.94	1.5
10033867	87-95		62cc			Aluminum, over the counter Pontiac 23′ head, angle plug, 196cc intake port
10045434	87		55cc			Aluminum, Over the counter Pontiac 15′ head, angle plug, raised runner, “rollover” head
10051101	87-95		55cc			Aluminum, Bowtie, angle plug, raised runner, 196cc intake port
10065202	87-95	350				Truck
10065203	88-up	350				Truck
10065204		350
10065205	90	305
10065206	86-91	350		1.94	1.5001	EFI
10065207	91-up	305
10088113	87-95	350	58cc	1.94	1.5	Aluminum, angle plug, raised “D” port exhaust
10093328	94-96		61cc			Aluminum, Over the counter Pontiac 15′ head, 224cc ports, “roll over” head
10106178	92-up	350				Aluminum, LT5, ZR1, DOHC, 32-Valve, pass. Side.
10106179	Bowtie	350				Aluminum, LT5, ZR1, DOHC, 32-Valve, drivers Side.
10110810	95-98	350	65cc			Gen. 1
10120928	87-95	350
10125320	87-95	350				Gen.II LT1, cast iron version, used on “9C1” Police package, Impala SS, Cadillac Fleetwood, Buick Roadmaster, reverse flow cooling
10128374	87-95	350	53cc			Aluminum, Gen.II LT1, angle plug, reverse flow cooling, 175/68cc ports
10134352	87-95		45cc			Aluminum, angle plug, “low” port, 223cc intake port, 18′ race head
10134363	91-94					This casting # has been used in many different versions of this aluminum 18′ and 15′ Bowtie race head. Different chamber volumes, port volumes, port locations, valve sizes, etc. were used. Check this casting carefully to determine which features it may have. There are at least 6 different versions as of 11/99
10147898	91-95	350				Gen.I crate motor
10159550	Bowtie	350
10159551	Bowtie	305
10159552	93	350
10159553	94-96	305
10174389	94-96	350				Aluminum, LT5, ZR1, DOHC, 32-Valve, pass. Side.
10174390	97	350				Aluminum, LT5, ZR1, DOHC, 32-Valve, drivers Side.
10185040	94-95		45cc			Aluminum, Bowtie, 1st version, symmetrical ports, 263cc intake ports, splayed valves
10205245	96-up	350	68cc			Aluminum, Gen.II LT1, reverse flow cooling, 175/68cc port volumes
10207643	96-up	350	68cc			Aluminum, Gen.II LT1, reverse flow cooling, 175/68cc port volumes
10208890	99-up	265				Gen.II, L99, 4.3 Liter V8, cast iron, reverse flow cooling
10215339	99-up	350	68cc			Aluminum, Gen.III, LS1,
10225121	2000	350				Aluminum, LT5, ZR1, DOHC, 32-Valve, Drivers Side.
10225122	97-up	350				Aluminum, LT5, ZR1, DOHC, 32-Valve, Pass. Side.
10239902	87-95	350	54.4cc			Aluminum, Gen.II LT4, reverse flow cooling, 195cc Intake port, angle plug.
10239906	87-94	350		1.94	1.5	Vortec 5700, “L31”, 170cc Intake port
12367712	87-95		62cc	2	1.55	Aluminum, FastBurn, 210cc Intake port
12367713	95-96		62cc	2	1.55	Aluminum, Fast Burn used on ZZ430 crate motor, 210cc Intake Port
12480005	96		38cc	2.125	1.65	Aluminum, Ls1″GTZ”, angle plug,
12480011	97-up		48cc			Aluminum, “SB2.2” 2nd version, “mirror ports” revised valve angles and plug location
12506450	94-96	350
12509859	95-96	305
12516852	96	350
12529742	99	265				Gen.II, L99, cast iron
12551561	97	350				Aluminum, Gen.II, “LT1”
12552520	98	305				Vortec, truck
12554290	97-98	350				Gen.II LT1, cast iron version, used on “9C1” Police package, Impala SS, Cadillac Fleetwood, Buick Roadmaster, reverse flow cooling
12554291	99-up	265				Gen.II, “l99” CAST IRON
12555690	99-00	350				Aluminum, Gen.II, “LT4”
12556743	00-up	325				Aluminum, Gen.III, 5.3L truck, van
12558059	4-Jan	305				Vortec, truck
12558062	99-01	350	68cc	1.94	1.5	L31 Vortec, 170cc Intake port, truck
12558806	4-Jan	350	68cc			Aluminum, Gen.III, “LS1”
12559853	00-up	350	68cc			Aluminum, Gen.III, “LS1”
12559862	01-up					Aluminum, GEN.III, 4.8/5.3L
12559895	4-Jan	325				Aluminum, Gen.III, Vortec, 5.3L
12561706	79-81					Aluminum, Gen.III, 5.3L
12561873	82-85	364	71cc			Iron, Gen.III
12562317	80-86	364	71cc			Aluminum, Gen.III
12564241	80	350	68cc			Aluminum, Gen.III, “LS1”
12564243	Bowtie	350, 364				Aluminum, Gen.III, “LS6”, “LS2”
12572035	82	364	71cc			Aluminum, Gen.III, 6.0L
14008856	Bowtie	267
14010201	55-86	305
14010516	80-81	350
14011034	80-85	350	64cc	2.02	1.6	Iron, 184cc intake ports, angle plug, “Phase II head”
14011049	80-86	350	55cc	2.02	1.6	Aluminum, 180cc intake port, angle plug, “Phase 6”
14011083	80	350	64cc	1.94	1.5	Crate motor for years indicated. 285/300HP
14014415	79-88	267, 305
14014416	80-86	267,305,350	58cc	1.85	1.5	4 barrel
14014440	80	305
14019261	81	350		1.94	1.5001
14019821	81	350
14019924	85	267
14019926	80	350
14020516	80-84	350
14020517	80-86	350
14020555	79-86	305, 350
14020556	80-82	350
14022056	80-86	350		1.94	1.5001
14022206	80-86	350
14022301	78-82	305		1.85	1.5
14022601	78-86	267,305		1.71	1.5
14022601	96-up	267, 305	53cc	1.72 or 1.84	1.84 or 1.5
14022801	80-86	305		1.71	1.5
14024816	80-86	350	76cc	1.94	1.5	Gen.I crate motors
14034806	81-86	267
14034807	81-86	305
14034808	80-86	350	76cc	1.94	1.5	Gen.I Goodwrench crate motors
14034810	86	350				Truck
14034811	80-86	350				Truck
14039121	86	305				Truck
14039122		305				Truck
14071114	86-88	350
14075381	86-88	350				Truck
14079261	55-86	350
14085844	86-91	350				Truck
14085963	87-95	350		1.94	1.5001
14088526	87	350				Aluminum, Gen.II, LT1
14089119	87-up	350		1.94	1.5001	EFI
14094093	86-87	350
14096217	87	350	64cc			Crate motor, 285/300hp, 72′ or 90′ center intake manifold bolt angels
14101081	86-91	305		1.84	1.5001	EFI, std port
14101083	86-88	350	64cc			Gen.I, also used on crate motors, 285/300hp, 72′ center manifold bolt angle.
14101083	88-93	350		1.94	1.5001	EFI
14101128	86-88	350		1.94	1.5001	EFI
14101128	87-up	350	58cc			Aluminum, angle plug
14102187	87-up	305		1.84	1.5001	EFI, swirl port
14102188	96-97	350		1.94	1.5001	EFI, swirl port
14102191	90-up	350		1.94	1.5001	EFI, swirl port
14102193	04-up	305, 350		1.94	1.5001	EFI
22542525	55					Aluminum, Dart/Olds/Chevy, 14′ or 17′ race head
24502559	57		38cc			Aluminum, Bowtie, “SB2”, 1st version, “mirror ports”, 196cc intake ports, CNC Version 280cc intake ports
25500141	60-63		42cc	2.1	1.65	Aluminum, Buick/Chevy, 10′ race head, symmetrical ports, 235cc intake ports
25534351C	69-70			2	1.55	cast iron Vortec head, Gen.I Bowtie, 175/65cc ports, small port head
25534371C	69-70			2	1.55	cast iron Vortec head, Gen.I Bowtie, 206/77cc ports, large port head
33417369	71-72	350	76cc			Gen.I Goodwrench crate motor, Hecho en Mexico
370r3523	71	265
3740r997	71	283				2×4 & FI (exc.-283hp)