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 NumberYearEngineChamber SizeIntake ValveExhaust ValveNotes
17645075-76262,3051.711.5
33054573307, 350741.721.5001245 or 250 Horsepower
33054571-7535076cc2.021.6
33086271-734001.941.5001
33388171-763501.721.5001165  or 270 Horsepower
33388174-7535076cc2.021.6
33388270-80350,4001.941.5137.5 CFM Intake and 95.4 CFM Exhaust
34029273-8064ccAngle plug, over the counter
35443475-80262, 267, 30560cc1.711.5
35874171-79262,3051.711.5
36745075-76262,3051.721.3
37644577-8535076cc1.721.5001Truck
37645075-81262, 267, 30560cc6 or 7 exhaust bolt holes
37649569-79350
38388271-73400
39938070-73400
42642472-82305,350,400
45862469-84350Truck
45864275-84350
46070378-80350
46261477-79305, 35060cc
46262475-873501.941.5Z-28 Camaro
46262478-813051.94 0R 2.021.6
46262479-8540076cc1.941.5
46864275-84350, 4001.721.5001
47151379-81267, 350
47242476-79305
51751379-82267, 350
181688763283Made in “Canada” GMC Truck
323888268-69350
329718557-673271.721.5001
329718563-67307,237,350
3636839552651.721.5
363683959265
3703523552651.721.5001
371335855-562651.721.5Truck
371356955-562651.721.5Truck
371448262-673271.721.5
372530656-572651.721.5Corvette
372718569-733071.721.5001
3731262562651.721.5Corvette 2 X 4 Barrel
3731539572831.721.5283 HP FI
373153957-66283
373154457-61265,2831.721.5
373155455-66265,2831.721.52 Barrel
3731556572831.721.5Made in “Canada” Truck
3731762562651.721.5001Corvette 2 X 4 Barrel
373746560-612831.721.5
373777562-67283, 3271.721.5
3740997572831.721.5
3743056582831.721.5Truck
374309662-673271.721.5GMC Truck
3747363572651.721.5
374736357-62283
374736358-61327Truck
374746059-67283, 32770cc
374805662-673271.721.5001
374872057-582831.5
374877058265
374877055-622831.721.5
374877257-612831.721.5
375553757-622831.721.52 Barrel
3755538592831.721.5001Corvette FI
375553958-622831.721.5Truck
375554957-622831.721.5
375555057-622831.721.5Corvette FI
375558562-673271.721.5GMC Truck
3760116592831.721.5
376746059-64265,283,327681.721.5
376746262-673271.941.5
376746559-612831.721.5001
376775459-6128360cc
376779260-672831.721.5
377012667-70327, 3501.941.5
3773012552651.721.5001Corvette
377463464-67327
377468260-67283, 32770cc1.721.5
377468457-67283,32775cc1.721.5Truck
377469058283Corvette fuel injection
377469258-6728360ccCorvette
377643464-67327
378246162-67302,327,35062cc1.6Camel hump, no accessory holes, 160/62cc port volumes
3782461X67283, 32762cc1.6Camel hump, no accessory holes, larger 172/64cc port volumes
378246262-67327
378287964-673271.941.5
379072165-672831.721.5
379256358-723271.721.5
379589362-64283,307,327
379589663-6528360cc
379589664-67283, 32760cc1.721.5
379689663-67283
37989966732760cc1.721.5
381446260-673501.941.5001
381448062-67283, 32770cc1.721.5Truck
381448259283, 32775cc1.721.5001Truck
381768062-67283, 3271.721.5Fuel Injection
381768166-673271.721.5
381768161-623501.721.5
3817682552831.721.52 Barrel
383683955-672651.721.5
383684262-67283, 3271.721.5
383692458-622831.721.5001
383694258-622831.721.5001
3837063562831.721.5001
383706455-62265, 2831.721.5
3837065572651.721.5Truck
383773962-672831.721.5
383777557-58283,3271.721.5001
3848720652831.721.5
384982065-673271.721.5001
384993562-642831.721.5
385217462-673271.721.5
385452068-76283,3271.721.5
385596157-603501.721.5
386780256-572831.721.5Corvette Fuel Injection
387306462-672651.721.5001
387613271-733271.941.5
387648757-673501.941.5001
387677560-67283,32775cc1.721.5Truck
387877560-67327Truck
388452062-68283, 32760cc1.721.5Some marked “Made in Canada”,  also used by Studebaker
389046262-67302,327,35064cc1.94 OR 2.021.6Camel hump, no accessory holes
389146264-67302,327,3501.941.5001
389149287-up327
39010686835064ccCrate motor, 285HP
3911011683271.721.5001
391103258-70307, 32770cc1.721.5Truck
391226463-642831.721.5
391226568-702831.721.5
391229165-67302,327,3501.941.5001
391231165-67327, 3501.941.5
391231365-733271.721.5
3914636673071.721.5
391726467-683022.021.6Z28 Camaro
391729068-70307, 3271.711.5Truck
391729167-69302, 307, 327, 35063cc1.941.5Camel hump, no accessory holes
391729267-68327, 35064cc1.941.5Camel hump
391729366-69307, 32775cc1.721.5
392117567-793272.021.6
392344168-73307,327,3501.711.5
392718569-76307,327,35070cc1.721.5
392718668-72302, 327, 35064cc2.021.6Camel hump, has accessory holes
392718769302, 35064cc2.021.6Camel hump, has accessory holes
392718868307,327,35074cc1.721.5Truck
39271887030774cc
3928454683071.721.5
392845568302,3272.021.6
392849468327,3502.021.6
392849568-733271.941.5
393163368-763071.721.5
393163568-693501.721.5
3931637683271.941.5
3931638683271.721.5Truck
393163968-733022.021.6
393237367-793071.721.5
393244168-72327, 35076cc1.941.5152 CFM Intake  93.2 CFM Exhaust
3932441X68-79350, 40080cc
393245476350Truck
393245468-73307,3501.721.5
3932882684001.941.5
393314869350
394117469-70327
394681269-793501.721.5Truck
394681368-703501.721.5Truck
394701468-70350
394704068-7932764ccRight angle casting identifier,, used in trucks,  no accessory holes
394704169-71302, 327, 35064cc1.941.5Right angle casting identifier,  accessory holes,
3947041X70-76302, 35064ccRight angle casting identifier,  165cc intake port,  accessory holes,
395159868-7740076cc1.941.52 barrel
396159870400
396428667-713501.721.5
396574267-79350Over the counter, angle plug L98 style
397012669-73327,3501.711.5CFM inl 148.3 / exh 87.6
397129364-70307,327
397319570400Truck
397337068-7235064ccOver the counter in US,  Canadian 350/300hp production use in Pontiac,  straight or angle plug
397341468-79327, 35064cc2.021.6Camel Hump, LT1-350/370hp
397348771-7635075cc1.94 or 2.021.5 or 1.6
3973487X62-6735075cc1.94 or 2.021.5 or 1.6
3973493674001.941.5CFM inl 143 / exh 87
397349371-7240076cc1.941.5
3981462713271.941.5
398146269-793021.941.5
398631668-6935076cc
398633070-76350
39863367135076cc
3986336X68-7135076cc
398633962-68307, 35074cc
398633968-763071.721.5
398633968-793501.721.5
3986339X68-73307, 35074cc
398638870-713501.711.5Truck
398638869-723071.721.5
3990462723271.941.5
399149272-75327,35064cc2.021.6LT1, Camel hump, accessory holes, straight plug
399741768-69307721.721.5001Cars
399891670-76350 , 40076cc1.941.5Also used w/’72 350 LT1, big valve, screw in studs
399892068-763501.941.5
399899171-73307, 35075cc1.721.5
399899368-76307, 35075cc
399899378-843501.941.5CFM inl 150 / exh 91
399899768-76305, 35076cc1.941.5
399899772-73350,4001.941.5
4079261350
62594253501.721.5
6259515350761.941.5001cars
626085687-953501.721.5
627207087-95350761.721.5001
891729187-95350641.941.5
1003386787-9562ccAluminum, over the counter Pontiac 23′ head, angle plug, 196cc intake port
100454348755ccAluminum, Over the counter Pontiac 15′ head, angle plug, raised runner, “rollover” head
1005110187-9555ccAluminum, Bowtie, angle plug, raised runner, 196cc intake port
1006520287-95350Truck
1006520388-up350Truck
10065204350
1006520590305
1006520686-913501.941.5001EFI
1006520791-up305
1008811387-9535058cc1.941.5Aluminum, angle plug, raised “D” port exhaust
1009332894-9661ccAluminum, Over the counter Pontiac 15′ head, 224cc ports, “roll over” head
1010617892-up350Aluminum, LT5, ZR1, DOHC, 32-Valve, pass. Side.
10106179Bowtie350Aluminum, LT5, ZR1, DOHC, 32-Valve, drivers Side.
1011081095-9835065ccGen. 1
1012092887-95350
1012532087-95350Gen.II LT1, cast iron version, used on “9C1” Police package, Impala SS, Cadillac Fleetwood, Buick Roadmaster, reverse flow cooling
1012837487-95350 53ccAluminum, Gen.II LT1, angle plug, reverse flow cooling, 175/68cc ports
1013435287-95 45ccAluminum,  angle plug, “low” port, 223cc intake port, 18′ race head
1013436391-94This 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
1014789891-95350Gen.I crate motor
10159550Bowtie350
10159551Bowtie305
1015955293350
1015955394-96305
1017438994-96350Aluminum, LT5, ZR1, DOHC, 32-Valve, pass. Side.
1017439097350Aluminum, LT5, ZR1, DOHC, 32-Valve, drivers Side.
1018504094-9545ccAluminum, Bowtie, 1st version, symmetrical ports, 263cc intake ports, splayed valves
1020524596-up35068ccAluminum, Gen.II LT1, reverse flow cooling, 175/68cc port volumes
1020764396-up35068ccAluminum, Gen.II LT1, reverse flow cooling, 175/68cc port volumes
1020889099-up265Gen.II, L99, 4.3 Liter V8, cast iron, reverse flow cooling
1021533999-up35068ccAluminum, Gen.III, LS1,
102251212000350Aluminum, LT5, ZR1, DOHC, 32-Valve, Drivers Side.
1022512297-up350Aluminum, LT5, ZR1, DOHC, 32-Valve, Pass. Side.
1023990287-9535054.4ccAluminum, Gen.II LT4, reverse flow cooling, 195cc Intake port, angle plug.
1023990687-943501.941.5Vortec 5700, “L31”, 170cc Intake port
1236771287-9562cc21.55Aluminum, FastBurn, 210cc Intake port
1236771395-9662cc21.55Aluminum, Fast Burn used on ZZ430 crate motor, 210cc Intake Port
124800059638cc2.1251.65Aluminum, Ls1″GTZ”, angle plug,
1248001197-up48ccAluminum, “SB2.2” 2nd version, “mirror ports” revised valve angles and plug location
1250645094-96350
1250985995-96305
1251685296350
1252974299265Gen.II, L99, cast iron
1255156197350Aluminum, Gen.II, “LT1”
1255252098305Vortec, truck
1255429097-98350Gen.II LT1, cast iron version, used on “9C1” Police package, Impala SS, Cadillac Fleetwood, Buick Roadmaster, reverse flow cooling
1255429199-up265Gen.II, “l99” CAST IRON
1255569099-00350Aluminum, Gen.II, “LT4”
1255674300-up325Aluminum, Gen.III,  5.3L truck, van
125580594-Jan305Vortec, truck
1255806299-0135068cc1.941.5L31 Vortec, 170cc Intake port, truck
125588064-Jan35068ccAluminum, Gen.III, “LS1”
1255985300-up35068ccAluminum, Gen.III, “LS1”
1255986201-upAluminum, GEN.III, 4.8/5.3L
125598954-Jan325Aluminum, Gen.III, Vortec, 5.3L
1256170679-81Aluminum, Gen.III, 5.3L
1256187382-8536471ccIron, Gen.III
1256231780-8636471ccAluminum, Gen.III
125642418035068ccAluminum, Gen.III, “LS1”
12564243Bowtie350, 364Aluminum, Gen.III, “LS6”, “LS2”
125720358236471ccAluminum, Gen.III, 6.0L
14008856Bowtie267
1401020155-86305
1401051680-81350
1401103480-8535064cc2.021.6Iron, 184cc intake ports, angle plug, “Phase II head”
1401104980-8635055cc2.021.6Aluminum, 180cc intake port, angle plug, “Phase 6”
140110838035064cc1.941.5Crate motor for years indicated. 285/300HP
1401441579-88267, 305
1401441680-86267,305,35058cc1.851.54 barrel
1401444080305
14019261813501.941.5001
1401982181350
1401992485267
1401992680350
1402051680-84350
1402051780-86350
1402055579-86305, 350
1402055680-82350
1402205680-863501.941.5001
1402220680-86350
1402230178-823051.851.5
1402260178-86267,3051.711.5
1402260196-up267, 30553cc1.72 or 1.841.84 or 1.5
1402280180-863051.711.5
1402481680-8635076cc1.941.5 Gen.I crate motors
1403480681-86267
1403480781-86305
1403480880-8635076cc1.941.5Gen.I Goodwrench crate motors
1403481086350Truck
1403481180-86350Truck
1403912186305Truck
14039122305Truck
1407111486-88350
1407538186-88350Truck
1407926155-86350
1408584486-91350Truck
1408596387-953501.941.5001
1408852687350Aluminum, Gen.II, LT1
1408911987-up3501.941.5001EFI
1409409386-87350
140962178735064ccCrate motor, 285/300hp, 72′ or 90′ center intake manifold bolt angels
1410108186-913051.841.5001EFI, std port
1410108386-88350 64ccGen.I,  also used on crate motors, 285/300hp, 72′ center manifold bolt angle.
1410108388-933501.941.5001EFI
1410112886-883501.941.5001EFI
1410112887-up350 58ccAluminum, angle plug
1410218787-up3051.841.5001EFI, swirl port
1410218896-973501.941.5001EFI, swirl port
1410219190-up3501.941.5001EFI, swirl port
1410219304-up305, 3501.941.5001EFI
2254252555Aluminum, Dart/Olds/Chevy, 14′ or 17′ race head
245025595738ccAluminum, Bowtie, “SB2”, 1st version, “mirror ports”, 196cc intake ports, CNC Version 280cc intake ports
2550014160-6342cc2.11.65Aluminum, Buick/Chevy, 10′ race head, symmetrical ports, 235cc intake ports
25534351C69-7021.55 cast iron Vortec head, Gen.I Bowtie, 175/65cc ports, small port head
25534371C69-7021.55 cast iron Vortec head, Gen.I Bowtie, 206/77cc ports, large port head
3341736971-7235076ccGen.I Goodwrench crate motor, Hecho en Mexico
370r352371265
3740r997712832×4 & FI (exc.-283hp)

 

 

 

Visually identifying the Chevy Small Blocks Heads.



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