Chevrolet Big Block

Block Casting Numbers

CASTING#…..SIZE…YEAR…MAIN CAP BOLTS….NOTES

0-326711…………………4-bolt, Alum., CanAm, 4.44″ bores, steel cylinder liners
340220…..427T……68-85…4-bolt
345014…..454…….70-86…
346236…..454…….75-76…2-bolt
359070…..454…….70-90…
361959…..454…….73-90…2 or 4 bolt
364776…..427T……68-85…4-bolt
364779…..366T……68-90…4-bolt
399204…..509…….70-71…4-bolt, Alum., CanAm, 4.5″ bores, steel Cylinder liners
399293…..366T……77-78…4-bolt
473478…..427T……77-90…4-bolt
495102…………………..4-bolt, Alum., CanAm, 4.5″ bores
3782870….427T……68-76…4-bolt
3824553….366T……66-67…4-bolt
3855961….396…….65-66…2 or 4 bolt
3855961….427…….66……2-bolt
3855962….396…….65-66…4-bolt
3855977….366T……66-73…4-bolt
3869942….427…….66-67…2 or 4 bolt
3902406….396…….67……2 or 4 bolt
3904351….427…….67……2 or 4 bolt
3904354….366T……66-76…4-bolt
3916319….366T……68……4-bolt
3916321….427…….68……2 or 4 bolt
3916323….396…….68……2 or 4 bolt
3925521….427T……68-85…4-bolt
3935439….427…….68-69…2 or 4 bolt
3935440….396…….68-69…2 or 4 bolt
3937724….366T……68-85…4-bolt
3937726….427T……68-84…4-bolt
3946052….427…….69……4-bolt, Alum. ZL-1, Mark IV
3946053….427…….97-up…4-bolt, Alum. ZL-1, 2nd version, Mark IV
3955270….427…….69……2 or 4 bolt
3955272….396…….69……2 or 4 bolt
3955274….366T……68-85…4-bolt
3955276….427T……68-73…4-bolt
3963512….427…….69……2 or 4 bolt
3963512….454…….70-76…2 or 4 bolt
3969852….366T……68-84…4-bolt
3969854….396…….69……2 or 4 bolt
3969854….402…….70-72…2 or 4 bolt
3969858….427T……68-84…4-bolt
3999289….454…….71-79…2 or 4 bolt, some ”CE” replacement blocks had four bolt main caps
3999290….396…….68-69…2 or 4 bolt, Truck
3999290….402…….70-72…2 or 4 bolt, Truck
3999290….402…….72……2 or 4 bolt, Passenger
3999293….366T……68-90…4-bolt
3999294….427T……68-84…4-bolt
10051107…454……………4-bolt, Bowtie, MkIV, 9.8″ deck, siamesed bores, 4.25″ semi-finished bores, can be bored to 4.50″
10069282…366T……90-91…4-bolt, Mark IV, Tall deck
10069284…427T…………..4-bolt, Mark IV, Tall deck
10069286…454…….90-91…4-bolt, Mark IV, Short deck
10114182…454…….91-up…4-bolt, Gen.V
10114183…366T……91-up…4-bolt, Gen.V
10114184…427T……91-up…4-bolt, Gen.V
10134366…454T…………..4-bolt, Bowtie, Gen.V, Tall deck
10185050…454……………4-bolt, Bowtie, Gen.V, Short deck
10237297…454…….96-up…4-bolt, Vortec 7400″, ”L-29” Gen.VI
10237299…427T……96-up…4-bolt, Gen.VI, 7.0L, truck
10237300…502…….96-up…4-bolt, Gen.VI, 4.466″ bore
12550312…427T……96-up…4-bolt, Gen.VI, 4.250″ bore, fuel pump boss, clutch linkage pivot boss
12550313…454…….91-up…4-bolt, Gen.V crate motor, Gen. VI 4.25″ bare block, fuel pump boss
12556110…496…….01-up…4-bolt, Gen.VII 8.1L, ”Vortec 8100”, Truck
12561357…454…….96-up…4-bolt, Gen.VI
12561358…502……………4-bolt, Gen. VI
14015443…454…….87-90…2 or 4-bolt, Mark IV, Truck, Motorhome
14015445…454…….78-90…2 or 4 bolt
14044807…454T…………..4-bolt, Bowtie, MkIV, CNC prep, Tall deck, 4.25″ bore or 4.495″ bores
14096859…502……………4-bolt, Gen.V, HO
24502504…454……………4-bolt, Bowtie, Gen.V, Race prep, 9.8 ”short” deck height
24502506…454T…………..4-bolt, Bowtie, Gen.V, Race prep, 10.2 ”tall” deck height
24502572…………………4-bolt, 4.5″ bore Olds DRCE 2, 9.5″ deck height
25534402…………………4-bolt, 4.590″ bore Olds DRCE 3, 9.25″ deck height

T = Tall deck, 10.2″ deck height

1991 and later Gen.V, VI and VII production BBC motors have one-piece rear main crank seals.

Cylinderhead Casting Number

CASTING#….YEAR….NOTES

330864…..68-84…oval…OPEN…396, 402, 366T,427T, 454 Truck
330865…..68-84…oval…OPEN…396, 402, 366T,427T, 454 Truck
330866…..68-78…oval…OPEN…366T, 427T
330867…..68-73…oval…OPEN…427T
336765…..68-78…oval…OPEN…427T
336768…..73-76…oval…OPEN…427T
336781…..73-85…oval…OPEN…454, 118cc chamber, 256/114cc ports
343771…..68-86…oval…OPEN…366T, 427T, 454
343772…..68-86…oval…OPEN…366T, 427T, 454
343783…..70-76…oval…OPEN…454 Truck
346236…..75-87…oval…OPEN…454, 120cc chamber, 225/116cc ports
352625…..70-76…oval…OPEN…454 Truck
353049…..73-84…oval…OPEN…454, 122cc chamber, 255/119cc ports
366765…..74-78…oval…OPEN…427T
473328…..68-69…oval…OPEN…366T
3856206….65-66…oval..CLOSED..396, 97cc chamber
3856208….65……rect..CLOSED..396/425hp, 109cc chamber, 396/375hp ”Z-16” Chevelle
3856213….66-82…oval..CLOSED..366T, 427T
3856260….68……oval..CLOSED..396 Truck
3872702….65-66…oval..CLOSED..396, 427, 98cc chamber
3873858….65-67…rect..CLOSED..396, 427, 109cc chamber
3876875….77-85…oval…OPEN…427T
3904390….67……oval..CLOSED..396, 427, 98cc chamber
3904391….67……rect..CLOSED..396, 427, 107cc chamber
3904392….67……rect..CLOSED..427, Aluminum, L88, L89, 107cc chamber
3904393….68-76…oval…OPEN…366T
3908952….67……oval…OPEN…427, ”M.Truck”, Marine
3909802….67……oval..CLOSED..396, 427, 101cc chamber
3917215….67-68…oval..CLOSED..396, 427, 101cc chamber
3917219….68-85…oval…OPEN…366T, 427T
3919840….67-69…rect..CLOSED..396, 427, 107cc chamber
3919842….68-69…rect..CLOSED..396, 427, Aluminum L88, L89, 107cc chamber
3931063….68-69…oval..CLOSED..396, 402, 427, 101cc chamber
3933148….69-84…oval…OPEN…’69 396/265hp, 366T, 427T, 112cc chamber
3933149….68-76…oval…OPEN…427T, 122cc chamber
3935401….68-76…oval…OPEN…427T
3946074….69&71…rect…OPEN…’69 427 L88, ZL1, Aluminum, 118cc chamber
’71 454 LS6, ”round exhaust port”
3964290….69-70…oval..CLOSED..396, 402, 427, 454, 101cc chamber, Large or small hex spark plugs used
3964291….69-72…rect..CLOSED..396, 402, 427, 454, 109cc chamber, Large or small hex spark plugs used, cratemotor usage in years after 1970.
3965198….68-69…oval..CLOSED..396 Truck
3975950….68-70…oval…OPEN…396, 402 Truck, 366T, 427T
3986133….68-85…oval…OPEN…366T, 427T, 454 Truck
3986135….69-73…oval…OPEN…366T, 427T
3986136….68-84…oval…OPEN…366T, 427T, 454 Truck
3993820….71……oval…OPEN…402, 113cc chamber, 255/114 ports
3993820….71-84…oval…OPEN…454 Passenger and Trucks, 113cc chamber, 255/114 ports
3994026….71……rect…OPEN…454 LS6, 118cc chamber
3999241….72……oval…OPEN…402, 454, 113cc chamber
6272292….70-78…oval…OPEN…402, 454
6272990….70-up…rect…OPEN…454 service replacement, used on some MKIV crate engines, 118cc chamber
10045427………..rect……….Pontiac/Chevy Aluminum, 91cc chamber, Large Port, race
10049875………..rect……….Pontiac/Chevy Aluminum, Small port, race
10051128………..rect……….Bowtie, Aluminum 72cc chambers, Symmetrical ports
10051129………..rect……….Bowtie, Aluminum ”raw”casting, Symmetrical ports
10052902………..oval…OPEN…MkIV, 427T
10101140…91-up…oval..CLOSED..Gen.V 366T, 427T
10114156…91-up…oval…OPEN…Gen.V & VI 454, 118cc chamber
10141279…96-up…oval..CLOSED..”Vortec 7400″, 100cc chambers
10487052…77-90…oval…OPEN…366T
12363391…96-up…oval…OPEN…Bowtie, Aluminum, SignatureSeries, fits MKIV, Gen.V, Gen.VI, 110cc chamber
12363401…96-up…rect…OPEN…Bowtie, Aluminum, SignatureSeries, fits MKIV, Gen.V, Gen.VI, 118cc chamber
12558162…01-up…oval..CLOSED..Gen.VII,”Vortec 8100″, 8.1L, 496, truck
12560241…98-up…oval..CLOSED..”Vortec 7400″, 100cc chambers
12562932…91-95…oval…OPEN…Gen.V, truck crate motor, 118cc chambers
12562933…91-95…oval…OPEN…Gen.V, 118cc chambers
12562934…00-up…rect…OPEN…Gen.VI 502 Marine
14011077…69-up…rect…OPEN…Aluminum, fits MKIV, ”C-port”118cc chamber, also sold as a ”solid” head
14044861…84-96…rect……….Bowtie, Aluminum, MkIV, ”raised runners”, 1st design, 105cc chamber
14044861…96-up…rect……….Bowtie, Aluminum, SignatureSeries, fits MKIV, Gen.V, Gen.VI”raised runners”, 2nd design, 115cc chamber
14044861…84-96…rect……….Bowtie, Aluminum, MkIV”raw” casting of ”861” MKIV1st design
14081045…78-87…oval…OPEN…454
14081052…85-87…oval…OPEN…366T, 427T, 454 Truck, Marked ”HiPerf”
14092359…86-90…oval…OPEN…366T, 427T, Marked ”HiPerf”
14092360…86-90…oval…OPEN…454 Truck, ”peanut” round ports
14096188…70-71…rect…OPEN…454 service replacement, also used on later Mark IV LS-6, LS-7 and 454 HO crate motors, 116cc chamber
14097088…91-up…rect…OPEN…Gen.V 454/502 HO, 118cc chamber
24502585…97……rect……….Olds/Chevy, DRCE 2,
Pro Stock aluminum, for blocks w/4.900″ bore spacing
25534404…04……rect……….Olds/Chevy, DRCE 3, Pro Stock, aluminum, for blocks with 4.900″ bore spacing

T = Tall deck

Oval includes both ”peanut” (also called ”round”) ports and large oval ports

Crankshaft Cast Number

BBC TWO PIECE REAR MAIN OIL SEALS
3.76″ STROKE used on ’65-’90 Mark IV 366T, 396, 402, 427 or 427T

6223…….396,402,427…forged, 1053 steel
7115…….396,402,427…forged, nitrided, cross-drilled, 5140 steel
3804816….396,402,427…cast
3856223….396…forged
3863114….402…
3863144….396,402…
3874874….396,402…
3879621….427…forged
3882841….396…forged, cross drilled, nitrided
3882842….427…forged, cross drilled, nitrided
3882847….
3882848….
3882849….427…forged
3887114….396…forged, nitrided, 5140 steel
3904815….396,402…cast, nodular iron
3941180….
3942411….
3965746……….semi finished, forged
3993804……….raw, 5140 steel

BBC ONE PIECE REAR MAIN OIL SEAL
3.76″ STROKE used on ’91-up Gen.V and Gen. VI 366T, 427T

10114186…427T…forged, 1053 steel
10114187…366T…cast
10114189…427T…cast

TWO PIECE REAR MAIN OIL SEALS
4.00″ STROKE used on ’70-90 Mark IV 454 or Mark IV 502

3520…….454…forged, cross-drilled, 1053 steel
3521…….454, 502…forged, cross-drilled, 5140 steel
3524…….454…forged
7416…….454, 502…forged, cross-drilled, 1053 steel
7463…….454…forged
336782…..454…cast
353039…..454…cast
353638…..454…
359730…..454…
3962523….454…forged
3963523….454…
3963524….454…forged
3967416….454…forged
3967463….454…forged
3975945….454
3963521….454…forged, cross drilled, 5140 steel
3965753……….semi finished, forged, 5140 steel
3975495….454
3993878….454…forged
10051169…454…forged raw casting

ONE PIECE REAR MAIN OIL SEAL
4.00″ STROKE used on ’91-up Gen.V and VI 454 or 502
10114188…454……cast
14097044…454,502..forged, 1053 steel

CHEVY 348-409 ”W” MOTOR V-8 Crankshaft Casting Numbers
3732692…348…forged…3.25″ stroke
3733223…348…forged…3.25″ stroke
3733226…348…forged…3.25″ stroke
3741640…348…forged…3.25″ stroke
3741642…348…forged…3.25″ stroke
3788072…409…forged…3.50″ stroke
3795589…409…forged…3.50″ stroke
3824553…348…forged…3.25″ stroke
3829027…409…forged…3.50″ stroke
3837466…409,427 ”Z11″…forged…3.65” stroke
3838416…409…forged…3.50″ stroke