BBC BLOCK CASTING NUMBERS
BLOCKS

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, Cylinder liners
399289.....454.......73-79
399293.....366T......77-78...4-bolt
473478.....427T......77-90...4-bolt
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......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.......72-79...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 cylinder barrels, 4.25" semi-finished bores, can be bored to 4.50"
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
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...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.





 Heads

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....69-70...rect..CLOSED..396, 402, 427, 454, 109cc chamber Large or small hex spark 
plugs used
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, Signature Series, fits MKIV, Gen.V, Gen.VI, 110cc chamber
12363401...96-up...rect...OPEN...Bowtie, Aluminum, Signature Series, 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
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, Signature Series, fits MKIV, Gen.V, Gen.VI "raised runners", 2nd design, 115cc chamber
14044861...84-96...rect..........Bowtie, Aluminum, MkIV "raw" casting of "861" MKIV 1st 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...86-88...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