Head casting numbers and the head casting date are located under the valve covers, in the rocker arm valley.
| Number | Year | Engine | Valves | Details |
|---|---|---|---|---|
| 10033867 | Over the counter Pontiac 23' head, 62cc, angle plug, 196cc intake port, aluminum | |||
| 10045434 | 55cc, angle plug, raised runner, aluminum,roll over head | |||
| 10051101 | Bowtie, aluminum, 55cc, angle plug, raised runner, 196cc intake port | |||
| 10088113 | 88-up | 350 | D port exhaust, 1.94/1.5 valves | |
| 10093328 | Over the counter, Pontiac 15' head, aluminum,224cc ports, 61cc chambers, roll over head | |||
| 10106178 | 90 | 350 | LT5, ZR1, DOHC, 32-valve, pass. side, aluminum | |
| 10106179 | 90 | 350 | LT5, ZR1, DOHC, 32-valve, drvs. side, aluminum | |
| 10110810 | 93-up | 350 | ||
| 10125320 | 94-96 | 350 | on 9C1 Police package, Impala SS, Cadillac Fleetwood, Buick Roadmaster, reverse flow cooling | |
| 10128374 | 92-up | 350 | aluminum, reverse flow cooling, 175/68cc ports | |
| 10134352 | Bowtie, 45cc, angle plug, low port, 223cc intake port, aluminum, 18' race head | |||
| 10134363 | This block number has been used in many different versions of this aluminum 18 deg and 15 deg Bowtie race head. Different chamber volumes, port volumes, port locations, valve sizes, etc. were used. Check this castingcarefully to determine which features it may have. There are at least 6 different versions as of 11/99. | |||
| 10147898 | 95-96 | 350 | ||
| 10174389 | 91-94 | 350 | drvs. side, aluminum | |
| 10174390 | 91-95 | 350 | pass. side, aluminum | |
| 10185040 | Bowtie, aluminum, 45cc chambers, 1st version, symmetrical ports, 263cc intake ports, splayed valves | |||
| 10185040 | Bowtie, aluminum, 45cc chambers, 2nd version, symmetrical ports, 240cc intake ports, splayed valves | |||
| 10205245 | 93 | 350 | Gen.II LT1, aluminum, reverse, flow cooling, 175/68cc port volumes | |
| 10207643 | 94-96 | 350 | ||
| 10215339 | 97 | 350 | Gen.III,LS1, aluminum | |
| 10225121 | 94-95 | 350 | drvs. side, aluminum | |
| 10225122 | 95 | 350 | LT5, ZR1, DOHC, 32-valve, pass. side, aluminum | |
| 10239902 | 96-up | 350 | Reverse flow cooling, 195cc port, 54.4cc chamber, angle plug | |
| 10239906 | 96-up | 350 | 170cc intake port, 1.94/1.5 valves | |
| 12367713 | 99-up | Fast Burn used on ZZ430 crate motor, aluminum, 210cc intake port, 2.00/1.55 valves, 62cc chamber | ||
| 12480005 | 2000 | LS1GTZ, aluminum, 38cc, 2.125/1.625 valves, angle plug | ||
| 12480011 | 97-up | Bowtie SB2.2, aluminum, 2nd version of SB2, 48cc chambers, mirror ports, revised valve angles and plug location | ||
| 12551561 | 96 | 350 | Gen.II,LT1, aluminum | |
| 12552520 | 97-up | 305 | ||
| 12554290 | 94-96 | 350 | on 9C1 Police package, Impala SS, Cadillac Fleetwood, Buick Roadmaster, reverse flow cooling | |
| 12555690 | 96 | 350 | Gen.II,LT4, aluminum | |
| 12558059 | 97 | 305 | Vortec, truck, 1.84/1.5 valves, 64cc chamber | |
| 12558062 | 98 | 350 | L31 Vortec, truck, 64cc chambers, 1.94/1.5, 170cc intake port | |
| 12558806 | 97-98 | 350 | ||
| 12559853 | 99 | 350 | Gen.III,LS1, aluminum | |
| 14010201 | 84 | 305 | ||
| 14011034 | 80 | 350 | 2.02 / 1.6 | Bowtie, cast iron, 64cc chambers, 184cc port volume, angle plug, Phase II head |
| 14011049 | 82 | 350 | 2.02 / 1.6 | Bowtie, aluminum, 55cc chambers, angle plug, 180cc ports, Phase 6 |
| 14011083 | 55-86 | 350 | 1.94/1.5 | 285/300hp |
| 14014415 | 80-85 | 267 - 305 | ||
| 14014416 | 80-86 | 267 - 305 - 350 | 1.84/1.5 | |
| 14014440 | 80 | 305 | 1.84/1.5 | |
| 14020516 | 80 | 350 | ||
| 14020517 | 80 | 350 | ||
| 14020555 | 81 | 305 - 350 | ||
| 14020556 | 81 | 350 | ||
| 14020556 | 81-85 | 350 | ||
| 14022601 | 79-86 | 267 - 305 | 1.71 / 1.5 | 58cc chambers |
| 14022801 | 80-86 | 305 | 1.71 / 1.5 | |
| 14034808 | 96-up | 350 | ||
| 14071114 | 80-85 | 350 | ||
| 14079261 | 86 | 350 | ||
| 14085963 | 86 | 350 | ||
| 14089119 | 86-88 | 350 | ||
| 14094093 | 86-88 | 350 | ||
| 14094093 | 86-88 | 350 | ||
| 14096217 | 55-86 | 350 | 72' or 90' center intake manifold bolt angles | |
| 14101081 | 87-91 | 305 | ||
| 14101083 | 87-up | 350 | chambers, 72' center manifold bolt angles | |
| 14101128 | 86-87 | 350 | ||
| 14102187 | 87-91 | 305 | 1.84/1.5 | |
| 14102188 | 88- 93 | 350 centerbolt | ||
| 14102191 | 87-up | 305 - 350 | ||
| 14102193 | 87-up | 305 - 350 | ||
| 176450 | 75-76 | 262 - 305 | 1.71 / 1.5 | |
| 1816887 | 63 | 283 | Made in Canada, GMC HD truck | |
| 24502559 | 96-97 | Bowtie,SB2, 1st version, mirror ports, aluminum, 196cc port, CNC version 280cc port, 38cc chamber | ||
| 25500141 | Buick/Chevy aluminum 10' head, 42cc chambers, symmetrical ports, 235cc intake port volumes, 2.1/1.625 valves | |||
| 3030817 | 74 | 400 | 2-bolt | |
| 3238882 | 68-69 | 350 | ||
| 3297185 | 57-67 | 307 - 237 - 350 | ||
| 330545 | 71-75 | 350 | 1.94 / 1.5, 2.02/1.60 | 245, 250 hp |
| 330862 | 71-73 | 400 | 1.94 / 1.5 | |
| 333881 | 71-76 | 350 | 165, 270 hp | |
| 333881 | 74-75 | 350 | 2.02/1.60 | 76cc, |
| 333882 | 70-80 | 307 - 327 -350 -400 | 1.94 / 1.5 | 76cc CFM Inlet 137.5 / Exh 95.4 |
| 33417369 | 90-up | 350 | Hecho en Mexico, 76cc | |
| 3391635 | 68-76 | 305 | ||
| 340292 | 73-80 | 350 | 2.02 / 1.6 | Over the counter, angle plug, 64cc |
| 354434 | 75-76 76-79 |
262 305 |
1.71 / 1.5 | |
| 358741 | 71-79 | 262 - 305 | 1.71 / 1.5 | |
| 3636839 | 55 ?? 59 | 265 | ||
| 367450 | 75-76 | 262 | ||
| 3703523 | 55 | 265 | ||
| 3703524 | 55 | 265 | ||
| 3713358 | 55-56 | 265 | truck | |
| 3713569 | 55-56 | 265 | truck | |
| 3720991 | 56-57 | 265 | ||
| 3725306 | 56 -57 | 265 | corvette | |
| 3727185 | 69-73 | 307 | ||
| 3731262 | 56 | 265 | corvette 2 x 4 brl | |
| 3731539 | 57-66 | 283 | ||
| 3731544 | 55-61 | 265 - 283 | ||
| 3731548 | 57-62 | 283 | ||
| 3731554 | 57 58-62 |
283 283 |
||
| 3731556 | 57 | 283 | truck, Made in Canada | |
| 3731762 | 56 | 265 | Corvette 2 x 4 brl | |
| 3737465 | 60-61 | 283 | ||
| 3737739 | 57-62 | 283 | 283 and 283 Corvette F.I. | |
| 3737775 | 62-67 | 283 - 327 | ||
| 3740997 | 57 | 283 | 1x4, 2x4 and FI (exc.-283hp) | |
| 3743056 | 58 | 283 | truck | |
| 3743096 | 62-67 | 327 | GMC truck | |
| 3747363 | 57-62 | 265 - 327 | truck | |
| 3747460 | 59-67 | 283 - 327 | ||
| 3748720 | 57-58 | 283 | 1x4 or 2x4 bbl carb or F.I Corvette | |
| 3748770 | 55-61 58-62 57 |
265-283 283 283 |
||
| 3748772 | 57-62 | 283 | ||
| 3755537 | 57-62 | 283 | 2 brl | |
| 3755538 | 59 | 283 | corvette FI | |
| 3755539 | 58-62 | 283 | truck | |
| 3755549 | 57-62 | 283 | Car and truck | |
| 3755550 | 57-62 | 283 | corvette FI | |
| 3755585 | 62-67 | 327 | GMC truck | |
| 3756519 | 57-62 | 283 | 283 and 283 Corvette F.I. | |
| 3760116 | 59 | 283 | 1x4 bbl carb or F.I. Corvette | |
| 376445 | 80-84 | 350 | 1.71 / 1.5 | truck |
| 376450 | 75-81 | 262 - 267 - 305 | 6 or 7 exhaust bolt holes | |
| 376455 | 77-85 | 350 | ||
| 376495 | 69-79 | 350 | ||
| 3767460 | 55-67 | 265 - 283 - 327 | ||
| 3767462 | 62-67 | 327 | ||
| 3767465 | 59-61 | 283 | ||
| 3767754 | 59-61 | 283 | ||
| 3767792 | 60-67 | 283 | Car and truck | |
| 3770126 | 67-70 | 327 - 350 | ||
| 3773012 | 55 | 265 | corvette | |
| 3774682 | 60-67 | 283 - 327 | ||
| 3774684 | 57-67 | 283 - 327 | truck | |
| 3774684 | 62-64 | 283-327 | Chev. trucks and GMC | |
| 3774690 | 58 | 283 | corvette fuel injection | |
| 3774692 | 58-64 | 283 | corvette | |
| 3776434 | 64-67 | 327 | ||
| 3782461X | 60-63 | 283 - 327 | Camel hump, no accessory holes, slightly larger 172/64cc port volumes | |
| 3782461 | 61-70 | 302 - 307 - 327 - 350 | Camel hump, no accessory holes, 160/62cc port volumes | |
| 3782462 | 67 | 327 | ||
| 3782870 | 62-67 | 327 | 327 and 327 Corvette | |
| 3782879 | 62-67 | 327 | 327 and 327 Corvette | |
| 3789817 | 62-67 | 327 | 327 and 327 Corvette | |
| 3789935 | 57-62 | 283 | ||
| 3790721 | 64-67 | 283 | ||
| 3792563 | 65-67 | 327 | ||
| 3795893 | 58-72 | 283 - 307 - 327 | ||
| 3795896 | 63-72 | 283-307-327 | ||
| 3796896 | 64-67 | 283 | ||
| 3798996 | 63-67 | 327 | ||
| 3814462 | 67 | 350 | ||
| 3814480 | 60-67 | 283 - 327 | truck, 70cc chambers, 1.72/1.5 valves | |
| 3814482 | 62-67 | 283 - 327 - 350 | truck 75cc chambers | |
| 3817680 | 63-67 | 283 - 327 | 283 4 bbl and F.I. | |
| 3817681 | 62-67 | 327-350 | ||
| 3817682 | 61-62 | 283 | 2 brl | |
| 3836839 | 55 | 265 | ||
| 3836842 | 57-67 | 265-283-327 | ||
| 3836942 | 58-62 | 283 | ||
| 3837063 | 58-62 | 283 | ||
| 3837064 | 56-62 | 265 - 283 | ||
| 3837065 | 55-56 | 265 | truck | |
| 3837739 | 57 | 283 | 283 and 283 truck | |
| 3837775 | 62-67 | 283 - 327 | ||
| 383882 | 71-73 | 400 | ||
| 3848720 | 57-58 | 283 | truck | |
| 3849820 | 65 | 327 | ||
| 3849852 | 57-67 | 283 | ||
| 3849935 | 65-67 | 283 | ||
| 3852172 | 62-64 | 327 | ||
| 3854520 | 62-67 | 283 - 327 | ||
| 3855961 | 68-76 | 350 | 2-bolt | |
| 3858174 | 65-67 | 327 | ||
| 3864812 | 57-67 | 283 | 283 and 283 truck | |
| 3867802 | 57-60 | 283 | corvette Fuel Injection | |
| 3873064 | 56-57 | 265 | ||
| 3876132 | 62-67 | 327 | 327 and 327 Corvette | |
| 3876487 | 71-73 | 350 | ||
| 3876775 | 57-67 | 283 - 327 | truck | |
| 3878775 | 64-67 | 327 | truck | |
| 3884520 | 60-67 | 283 - 327 | Some marked Made in Canada, 60cc chamber, also used by Studebaker | |
| 3890462 | 62-68 | 302 - 327 - 350 | 1.94 / 1.5 or 2.02 / 1.6 | Camel hump, no accessory holes |
| 3891492 | 64-67 | 327 | ||
| 3892657 | 65-67 | 327 | ||
| 3896944 | 65-67 | 283 |
| Number | Year | Engine | Valves | Details |
|---|---|---|---|---|
| 3901068 | 87-up | 350 | Crate motor, 285hp, 64cc chamber | |
| 3911011 | 68 | 32 | ||
| 3911032 | 68-70 | 307 - 327 | truck | |
| 3912264 | 58-62 | 283 | 283 car and truck | |
| 3912265 | 63-64 | 283 | ||
| 3912291 | 68-70 | 302 - 327 - 350 | ||
| 3912311 | 65-67 | 327 - 350 | ||
| 3912313 | 65-73 | 327 | ||
| 3914636 | 68-73 | 307 | ||
| 3914660 | 68-69 | 327 | 327 and 327 Corvette | |
| 3914678 | 68-69 | 327 | 327 and 327 Corvette | |
| 3917264 | 67 | 302 | Z28 Camaro | |
| 3917290 | 67-70 | 307-327 | 1.71 / 1.5 | |
| 3917291 | 68-69 67-70 |
327-350 302-327 |
1.94 / 1.5 | Camel hump, no accessory holes |
| 3917292 | 67-68 | 327 - 350 | Camel hump | |
| 3917293 | 68-69 | 307 - 327 | 75cc chambers | |
| 3921175 | 66 | 327 | 327 (350 HP) | |
| 3923441 | 67-79 | 307 - 327 - 350 | 1.71 / 1.5 | |
| 3927185 | 68-76 | 307-327-350 | 70cc chambers | |
| 3927186 | 68-72 | 302-327-350 | 2.02 / 1.6 | Camel hump, 64cc chambers, accessory holes |
| 3927187 | 69-70 | 302 - 350 | Camel hump, 64cc chambers, accessory holes | |
| 3927188 | 69 | 307 - 327 - 350 | Light truck, 74cc chambers | |
| 3928454 | 68 | 307 | ||
| 3928455 | 68 | 302-327 | 325 HP and 350 HP | |
| 3928494 | 68 | 327 - 350 | 327 hi-performance 4 bbl and 350 | |
| 3928495 | 68 | 327 | 327 std. and 327 (250 HP) | |
| 3931633 | 68-73 | 307 | ||
| 3931635 | 68-76 | 350 | ||
| 3931637 | 68-69 | 327 | 327 and 327 Corvette | |
| 3931638 | 68 | 327 | truck | |
| 3931639 | 68 | 302 | ||
| 3932373 | 68-73 | 307 | ||
| 3932386 | 68-76 | 327 - 350 | 350 4-bolt and 327 Corvette | |
| 3932388 | 68-76 | 350 | 2-bolt | |
| 3932441 | 67-79 | 327 - 350 | 1.94 / 1.5 | CFM inl 152 / exh 93.2 |
| 3932441 | 67-72 | 327-350 | 76cc chambers | |
| 3932454 | 69-73 | 307 | truck | |
| 3932454 | 69-79 | 350 | truck | |
| 3932882 | 76 | 400 | ||
| 3933148 | 68-73 | 350 | ||
| 3941174 | 68 | 327 | ||
| 3946812 | 69 | 350 | truck | |
| 3946813 | 69-79 | 350 | truck | |
| 3947040 | 68 | 327 | Right angle casting identifier, 64cc chambers, good HP head, used in trucks, no accessory holes | |
| 3947041 | 68-79 | 327 - 350 | 1.94 / 1.5 | |
| 3947041 | 69-70 | 302 - 350 | Right angle casting identifier, 64cc, accessory holes, good HP head | |
| 3951509 | 74 | 400 | 2-bolt | |
| 3951511 | 70-73 | 400 | 4-bolt | |
| 3951598 | 70-71 | 400 | 2 barrel, 76cc chambers | |
| 3956618 | 68-76 | 350 | 4-bolt | |
| 3958618 | 68-76 | 350 | 2-bolt | |
| 3961598 | 70-76 | 400 | ||
| 3964286 | 68-77 | 350 | ||
| 3965742 | 70 | 350 | over the counter, angle plug | |
| 3970010 | 68-76 | 350 | 4-bolt | |
| 3970020 | 68-73 | 307 | ||
| 3970126 | 67-79 | 327 - 350 | 1.71 / 1.5 | CFM inl 148.3 / exh 87.6 |
| 3970721 | 64-67 | 283 | ||
| 3971293 | 68-69 | 307 - 327 | ||
| 3973195 | 71-73 | 400 | truck | |
| 3973370 | 69-70 | 350 | ||
| 3973414 | 64-70 | 327 - 350 | LT1-370hp, Camel hump, 64cc | |
| 3973487 | 68-71 71 |
350 350 |
1.94 / 1.5 or 2.02 / 1.6 | 350 high performance 350 trucks and passenger cars |
| 3973493 | 70-76 | 400 | 1.94 / 1.5 | 76cc, CFM inl 143 / exh 87 |
| 3981462 | 62-67 | 302-327-350 | ||
| 3986316 | 71-72 | 350 | 76cc | |
| 3986336X | 350 | 76cc | ||
| 3986339X | 71 | 307 - 350 | ||
| 3986330 | 69-79 | 350 | ||
| 3986339 | 68-79 | 307 - 350 | 1.71 / 1.5 | |
| 3986388 | 68-79 | 307 - 350 | 1.71 / 1.5 | truck |
| 3991492 | 68-73 | 327 - 350 | 1.94 / 1.5 or 2.02 / 1.6 | |
| 3991492 | 69-70 | 350 | LT1, Camel hump, accessory holes, 64cc, straight plugs | |
| 399380 | 70-73 | 400 | ||
| 3998916 | 72-75 | 350 - 400 | Also used w/'72 350 LT1, big valves, screw in studs | |
| 3998920 | 72-75 | 350 | 1.94 / 1.5 | |
| 3998991 | 68-76 | 307-350 | 75cc | |
| 3998993 | 68-79 | 350 | 1.94 / 1.5 | CFM inl 150 / exh 91 |
| 3998993 | 68-76 | 307 - 350 | 75cc chamber. Low performance cars and trucks | |
| 3998997 | 72-73 78-79 78-79 80-84 |
350 -- 400 305 350 350 |
1.94 / 1.5 | All 76cc |
| 4079261 | 75 | 350 | ||
| 426424 | 72-82 | 305 - 350 - 400 | ||
| 458624 | 69-84 | 350 | truck | |
| 460703 | 78-80 | 350 | ||
| 462614 | 77-79 | 305 - 350 | ||
| 462624 | 78-81 | 350 | 1.94 / 1.5 | Z-28 Camaro |
| 462624 | 76-87 | 305 - 350 | 1.94 / 1.5 r 2.02 / 1.6 | |
| 462624 | 75-86 | 350 - 400 | 76cc chamber | |
| 468642 | 75-84 | 350 - 400 | 1.71 / 1.5 | |
| 468642 | 76-79 80-84 |
350 350 |
||
| 471513 | 79-81 | 267 - 350 | ||
| 472424 | 76-79 | 305 | ||
| 517513 | 79-81 | 267 - 350 | ||
| 6259425 | 68-76 | 350 | 2-bolt | |
| 6260856 | 68-76 | 350 |
Another reference page Year One GM Engine ID