The block casting number on smallblock and big block Chevy V-8 motors is located on a ledge found at the rear of the block, most often on the driver's side. This ledge is below the deck of the block and the ledge forms the mating surface between the block and the transmission bellhousing. Some of the later model blocks have the casting number on the passenger side of this ledge.
The number itself can have 6, 7 or 8 numeral digits. They might look like this “361959” or “3970010” or “14015445”. The block casting numbers do not have any letters in them. There are sometimes other individual letters found on blocks like “GM” or “CFD” for the Central Foundry Division, but they are not part of the block casting number. Also some of the later blocks have the size of the motor shown in liters. You may see a “5.0” (305) or “5.7” (350) cast on the rear ledge of a smallblock or a “7.4” on the side of a big block 454.
On the side of some later blocks the last three digits of the block casting number are cast into the block, but these are difficult to see when the engine is in a vehicle.
| Casting Number |
Year | CID | Main Bolts |
Notes |
|---|---|---|---|---|
| 140029 | 80-84 | 350 | 2 | |
| 330817 | 70-80 | 400 | 2 | |
| 355909 | 75 | 262 | 2 | |
| 355909 | 76-79 | 305 | 2 | |
| 360851 | 75-76 | 262 | 2 | Monza V-8 |
| 361979 | 77-79 | 305 | 2 or 4 | Some Canadian assembled heavy duty blocks have 4-bolt main caps. |
| 366245 | 78-82 | 350 | 4 | Bowtie High Tin |
| 366286/7 | 350 | 4 | Bowtie, Aluminum, siamesed, straight nodular iron main caps 2-piece seal, 4.00-4.150 bores, 2.45 main journals | |
| 366298 | 4 | Bowtie, Aluminum, billet main caps,3.398 bore with sleeves, 2 piece rear seal | ||
| 366299 | 350 | 4 | Bowtie Aluminum nodular iron splayed caps wet sump 4.00 bore | |
| 389257 | 67 | 302 | 2 | |
| 393288 | 65-67 | 283 | 2 | |
| 460703 | 78 | 350 | 4 | |
| 460776 | 78-79 | 305 | 2 | |
| 460777 | 78-79 | 305 | 2 | |
| 460778 | 78-79 | 305 | 2 or 4 | Some Canadian assembled heavy duty truck blocks have 4-bolt main caps |
| 471511 | 79-82 | 267 | 2 | |
| 3556519 | 58-61 | 283 | 2 | |
| 3703524 | 55 | 265 | 2 | No oil filter |
| 3720991 | 56-57 | 265 | 2 | |
| 3731548 | 57 | 265 or 283 | 2 | No side motor mounts |
| 3737739 | 58-64 | 283 | 2 | |
| 3737739 | 57-62 | 283 only | 2 | |
| 3756519 | 58-62 | 283 | 2 | |
| 3782870 | 62-67 | 327 | 2 | |
| 3789817 | 62-64 | 283 or 327 | 2 | |
| 3789935 | 61-64 | 283 | 2 | |
| Casting Number |
Year | CID | Main Bolts |
Notes |
| 3790721 | 62-64 | 283 | 2 | Chevy II recessed oil filter boss |
| 3790721 | 65-66 | 327 | 2 | Chevy II recessed oil filter boss |
| 3791362 | 62-67 | 327 | 2 | Chevy II recessed oil filter boss |
| 3792563 | 65 | 327 | 2 | |
| 3792582 | 64-65 | 283 | 2 | |
| 3794226 | 58-63 | 283 | 2 | |
| 3794460 | 62-64 | 327 | 2 | |
| 3814660 | 68-69 | 327 | 2 | |
| 3830944 | 63 | 327 | 2 | |
| 3834810 | 64-66 | 283 | 2 | |
| 3834812 | 62-63 | 283 | 2 | |
| 3837739 | 58-62 | 283 | 2 | |
| 3849852 | 64-68 | 283 | 2 | |
| 3849935 | 65-67 | 283 | 2 | Truck |
| 3852174 | 62-64 | 327 | 2 | |
| 3858174 | 64-66 | 327 | 2 | |
| 3858180 | 64-67 | 327 | 2 | |
| 3858618 | 68-76 | 350 | 2 | |
| 3862194 | 65-67 | 283 | 2 | Chevy II recessed oil filter boss |
| 3862812 | 62-64 | 283 | 2 | |
| 3892657 | 67 | 302 | 2 | Z-28 Camaro, small journal |
| 3892657 | 67 | 327 | 2 | |
| 3892657 | 67 | 350 | 2 | Camaro |
| 3892657 | 64-67 | 350 327 & 302 | 2 | |
| 3896944 | 67 | 283 | 2 | |
| 3896948 | 66-67 | 283 | 2 | |
| 3903352 | 67 | 327 | 2 | |
| 3914636 | 68 | 307 | 2 | |
| 3914653 | 68-73 | 307 | 2 | |
| 3914660 | 68 | 327 | 2 | |
| 3914678 | 68 | 327 | 2 | |
| 3914678 | 68 | 302 | 2 | Z-28 Camaro |
| 3914678 | 68 | 350 | 2 | |
| 3932371 | 69-73 | 307 | 2 | |
| 3932373 | 68-73 | 307 | 2 | |
| 3932386 | 69 | 302 | 4 | Z-28 Camaro |
| 3932386 | 69 | 350 | 4 | |
| 3932388 | 69 | 350 | 4 | |
| 3951509 | 70-80 | 400 only | 2 or 4 | |
| 3951509 | 74-75 | 400 | 2 | |
| 3951509 | 70-71 | 400 | 4 | |
| 3951511 | 70 - 80 | 400 only | 2 or 4 | |
| Casting Number |
Year | CID | Main Bolts |
Notes |
| 3951511 | 70-71 | 400 | 2 or 4 | Some replacement blocks had 2-bolt main caps |
| 3956618 | 69 | 350 | 2 or 4 | |
| 3956618 | 68-69 | 327 | 2 | |
| 3956618 | 69 | 302 | 4 | Z-28 Camaro |
| 3956632 | 69 | 307 | 2 | |
| 3959512 | 62-67 | 327 | 2 | Was also used for some CE replacement blocks |
| 3959532 | 64 | 283 | 2 | Was also used for some CE replacement blocks |
| 3959538 | 327 | 2 | Chevy II recessed oil filter boss, Used for some Chevy II CE replacement blocks | |
| 3970010 | 69 | 302 | 4 | Z-28 Camaro |
| 3970010 | 69-80 | 327 | 2 | Trucks and industrial |
| 3970010 | 69-79 | 350 only | 2 or 4 | |
| 3970014 | 70-72 | 350 | 2 or 4 | Camaro |
| 3970014 | 68-79 | 350 | ||
| 3970020 | 69-73 | 307 | 2 | |
| 3970024 | 69-73 | 307 | 2 | |
| 4715111 | 80 | 305 | 2 | |
| 6259425 | 69-76 | 350 | 2 | |
| 10036033 | 350 | 4 | Goodwrench crate motor 2-piece rear seal "Hecho en Mexico" | |
| 10046164 | 86 | 305 | 2 | |
| 10049804 | 4 | Aluminum, Pontiac Super Duty version of Gen.I SBC, 4.00 bore, 350 mains, 2-piece rear seal, splayed caps, GTP race block | ||
| 10051182 | 2 or 4 | Bowtie, 3.75-4.30 bores, 1 or 2-piece rear seal | ||
| 10051184 | 4 | Bowtie, 4.00-4.155 bores, 1 or 2-piece rear seal | ||
| 10054727 | 86-up | 350 | 2 or 4 | one piece rear seal, some Made in Canada |
| 10066036 | 94 | 350 | 2 or 4 | Target Master/Goodwrench crate motor, 2-piece rear seal, Hecho en Mexico |
| 10066038 | 94 | 350 | 4 | Goodwrench crate motor, 2-piece rear seal, "Hecho en Mexico" |
| Casting Number |
Year | CID | Main Bolts |
Notes |
| 10090511 | 90 | 350 | 2 | LT-5, ZR1 Vette 375hp |
| 10125327 | 96-up | 350 | 2 or 4 | Gen.II LT-4 reverse flow cooling |
| 10125327 | 92-up | 350 | 2 or 4 | Gen.II LT-1 reverse flow cooling |
| 10134398 | 4 | Bowtie Aluminum 4.125 bore, 2.65 main journals | ||
| 10134996 | 4 | Bowtie Aluminum 4.125 bore 2.65 main journals | ||
| 10153558 | 91-92 | 350 | 4 | LT-5 ZR1 Vette 375hp |
| 10168588 | 94-96 | 265 | 2 | L99, Gen.II, 4.3 Liter V-8, Caprice, reverse flow cooling |
| 10199001 | 93-95 | 350 | 4 | LT-5 ZR1 Vette 405hp |
| 10243878 | 96-98 | 305 | 2 | Vortec truck, roller cam, one-piece rear seal |
| 10243880 | 95-00 | 350 | 2 or 4 | Vortec truck, Gen.I crate motors and ZZ4, roller cam, one piece rear seal |
| 12550592 | 97-up | 350 | crossbolted block, Gen.III, LS1, aluminum | |
| 12551358 | 99-up | 4.8 or 5.3 | Gen.III, 4.8L or 5.3L, cast iron, truck | |
| 12551364 | 99-up | 364 | crossbolted cast iron Gen. III, 6.0L, truck | |
| 12559378 | 99-up | 350 | crossbolted block, Gen.III, LS1, aluminum | |
| 12559846 | 98-up | 350 | crossbolted block, Gen.III, LS1, aluminum | |
| 12560621 | 98-up | 350 | crossbolted block, Gen.III, LS1, aluminum | |
| 12560626 | 99-up | 350 | crossbolted block, Gen.III, LS1, aluminum | |
| 12560629 | 99 | 350 | crossbolted block, Gen.III, LS1, aluminum | |
| 12561168 | 01-up | 350 | crossbolted block, Gen.III, LS1, aluminum | |
| 12562174 | 98-up | 350 | crossbolted block, Gen.III, LS1, aluminum | |
| 12568952 | 05-up | 364 | crossbolted block, Gen.III, 6.0L, aluminum, LS2 | |
| 12566910 | 04-up | 325 | crossbolted block, Gen.III, 5.3L, aluminum, SSR truck | |
| 12571048 | 04-up | 325 | crossbolted block, Gen.III, 5.3L | |
| 1253581 | 98-04 | 364 | crossbolted cast iron, Gen.III, 6.0L, truck | |
| 12577184 | 98-04 | 364 | crossbolted cast iron, Gen.III, 6.0L, truck | |
| 12577396 | 02-up | Gen.III, 4.8L or 5.3L, cast iron, truck | ||
| Casting Number |
Year | CID | Main Bolts |
Notes |
| 14010201 | 80-84 | 305 | 2 | |
| 14010202 | 80-84 | 305 | 2 | |
| 14010203 | 80-84 | 305 | 2 | |
| 14010207 | 80-85 | 350 | 2 or 4 | Truck |
| 14010209 | 80-85 | 350 | 4 | Truck |
| 14010280 | 79-82 | 267 | 2 | |
| 14011064 | 83 | 350 | 4 | |
| 14011064 | 82-86 | 350 | 4 | 4-Bolt main Bowtie High Tin |
| 14011064 | 83 | 350 | ||
| 14011148 | 87-89 | 350 | Roller cam one-piece rear seal | |
| 14016376 | 79-82 | 267 | 2 | |
| 14016379 | 77-79 | 350 | 2 or 4 | |
| 14016381 | 80-84 | 305 | 2 | |
| 14016382 | 79-84 | 305 | 2 | |
| 14016383 | 80-85 | 305 | 2 | Truck |
| 14079287 | 86-90 | 350 | Truck | |
| 14088526 | 86-88 | 350 | 2 or 4 | 1 piece rear main seal. |
| 14088584 | 86-88 | 350 | 2 or 4 | |
| 14088551 | 86-87 | 305 | 2 | one-piece rear seal |
| 14093627 | 87-94 | 305 | 2 | Roller or flat tappet cam one-piece rear seal |
| 14093638 | 87-95 | 350 | 2 or 4 | Roller or flat tappet cam, one-piece rear seal. |
| 14094766 | 86-up | 305 | 2 | One-piece rear seal |
| 14101147 | 85-up | 305 | 2 | |
| 14101148 | 86-90 | 350 | 4 | 1 piece rear main seal. |
| 14102058 | 87-91 | 305 | 2 | Roller cam, one-piece rear seal |
| 22551656 | 4 | Chevy/Olds Rocket block, 4.00-4.190 bores, 2.45 main journal sizes, splayed caps, dry sump, 2-piece rear seal, 9.025 deck | ||
| 22551660 | 4 | Chevy/Olds Rocket block, 4.00-4.190 bores, 400 mains journal sizes, splayed steel caps, wet sump, raised cam 2-piece rear seal, 9.300 deck |
Another reference page Year One GM Engine ID