330545.....73......350..........76cc chamber, 2.02/1.60
333881.....74-75...350..........76cc chamber, 2.02/1.60
333882.....74-80...350/400......76cc chambers
340292.....70's.......Over the counter, angle plug, 64cc chamber
354434.....75-79...262/267/305...60cc chambers
358741.....76-79...305
376445.....77-85...350..........76cc chamber, small valves
376450.....75-81...262/267/305..6 or 7 exhaust bolt holes, 60cc chamber
462614.....77-79...305..........60cc chamber
462624.....75-86...350/400......76cc chamber, 1.72/1.5, 1.94/1.5 or 2.02/1.6 valves
458642.....75-84...350..........350
468642.....76-up...350/400
471513.....79......267/350
517513.....79......267/350
1816887....63......283..........Made in "Canada", GMC HD truck
3636839....55......265
3703523....55......265
3713358....55-56...265
3713569....55-56...265
3725306....56......265
3731539....57......283..........283 HP FI
3731544....57-61...283
3731554....57-62...283
3731556....57......283..........Truck, Made in Canada
3731762....56......265..........Vette, 2x4 carbs
3737775....62-67...283/327
3740997....57......283..........1x4, 2x4 & FI (exc.-283hp)
3743056....58......283
3743096....62-67...327..........GMC Truck
3747363....57-61...283
3747460....59-67...283/327......70cc chambers
3748770....58......283
3748772....58-61...283
3755537....57-62...283
3755539....58-62...283
3755549....57-62...283
3755550....59......283
3755585....62-67...327..........GMC Truck
3767460....59-60...283
3767462....62-67...327
3767465....59-61...283
3767754....59-61...283..........60cc chambers
3767792....60-64...283
3774682....60-64...283/327......70cc chambers
3774684....62-64...327..........75cc chambers
3774692....58-64...283..........60cc chambers
3782461....64-66...327......Camel hump,no accessory holes,160/62cc port volumes,62cc chamber
3782461X...60-63...283/327..Camel hump,no accessory holes,larger 172/64cc port volumes, 62cc chamber
3795896....63-65...283......60cc chamber
3795896....62-64...327......60cc chamber
3798996....63-67...327
3814480....60-67...283/327..70cc chambers, 1.72/1.5 valves
3814482....62-67...283/327/350..75cc chambers
3817680....63-67...283/327
3817681....62-67...327
3817682....61-62...283
3836839....55......265
3836842....57-67...283/327
3837064....56-62...265/283
3837065....55-56...265..........Truck
3848720....57-58...283
3876775....60-67...283/327......75cc chamber
3884520....60-67...283..........Some marked "Made in Canada", 60cc chamber, also used by Studebaker
3884520....62-67...327..........Some marked "Made in Canada", 60cc chamber, also used by Studebaker
3890462....66-67...302/327/350..Camel hump,no accessory holes,64cc chamber
3901068....87-up...350..........Crate motor, 285hp, 64cc chamber
3911032....68......307/327......70cc chamber
3912264....58-62...283
3912265....63-64...283
3912311....65-67...327
3912313....65-67...327
3917290....67-68...307/327
3917291....67-68...302/327/350..Camel hump,no accessory holes,64cc chamber
3917292....68......327/350......Camel hump,64cc chamber
3917293....67-68...307/327......75cc chambers
3927185....69-76...307/327/350..70cc chambers
3927186....69-70...302/350......Camel hump,64cc chambers,accessory holes
3927187....69-70...350..........Camel hump,64cc chambers,accessory holes
3927188....69......327..........74cc chambers
3927188....70......307..........74cc chambers
3931633....68-73...307
3931635....68-76...350
3931638....68......327..........Truck
3932441....69-70...350..........76cc chambers
3932441X...69-70...350/400......80cc chambers
3932454....69-73...307
3932454....69-79...350..........Truck
3946812....69......350
3946813....69-79...350..........Truck
3947040....68......327.........."Right angle" casting identifier, 64cc chambers, good HP head,
used in trucks, no accessory holes
3947041....69-70...302/350......"Right angle" casting identifier, 64cc chamber, accessory holes, good HP head
3947041X...69-70...302/350......"Right angle" casting identifier, 64cc chamber, 165cc intake port, accessory holes, good HP head
3951598....70......400..........76cc chambers
3964286............350
3965742....70......350..........over the counter, angle plug
3970126....67-71...327/350
3973370....69-70...350..........over the counter in US, Canadian 350/300hp production use in Pontiac, 64cc, straight or angle plug
3973414....70......350..........LT1-350/370hp, Camel hump, 64cc chamber
3973487....71-72...350..........1.94/1.5 or 2.02/1.6 valves, was also used on '71 350/330hp LT1, 75cc chamber
3973487X...71-72...350..........1.94/1.5 or 2.02/1.6 valves, 75cc chamber
3973493....71-72...400..........76cc chamber
3986316....71......350..........76cc chamber
3986336....71......350..........76cc chamber
3986336X...71......350..........76cc chamber
3986339....71......307/350......74cc chamber
3986339X...71......307/350......74cc chamber
3986388....68-76...307/350
3991492....70......350..........LT1,Camel hump,accessory holes,64cc, straight plug
3991492....70-up................over the counter,Camel hump,64cc, straight or angle plug
3998916....72......350..........also used w/'72 350 LT1, big valves, screw in studs, 76cc chambers
3998920....72-73...350
3998991....72-73...307/350......75cc chambers
3998993....72-73...307/350......75cc chambers
3998993....current..350.........Goodwrench crate motors,"Hecho en Mexico", 75cc chambers
3998997....72-73...350/400......76cc chambers
3998997....78-84...305/350......76cc chambers
4079261....75......350
10033867........................Aluminum,over the counter Pontiac 23' head,62cc,angle plug, 196cc intake port
10045434........................Over the counter Pontiac 15' head
55cc, angle plug, raised runner
aluminum, "roll over" head
10051101........................Bowtie, aluminum, 55cc, angle plug
raised runner, 196cc intake port
10065202...87-95...350..........Truck
10065203...87-95...350..........Truck
10065204...87-95...350
10065205...87-95...305
10065206...87-95...350
10065207...87-95...305
10088113...88-up...350..........Aluminum, 58cc, angle plug, raised
"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...91-up...350..........Gen. 1, 65cc chambers
10120928...87-95...350
10125320...94-96...350..........Gen.II LT1, cast iron version, used
on "9C1" Police package, Impala SS,
Cadillac Fleetwood, Buick Roadmaster
reverse flow cooling
10128374...92-up...350..........Gen.II LT1, 53cc, angle plug,
aluminum, reverse flow cooling,
175/68cc ports
10134352........................Bowtie, 45cc, angle plug, "low"
port, 223cc intake port, aluminum,
18' race head
10134363........................NOTE: This 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.
10147898...95-98...350..........Gen.I crate motor
10159550...87-95...350
10159551...87-95...305
10159552...87-95...350
10159553...87-95...305
10174389...91-94...350..........LT5, ZR1, DOHC, 32-valve,
drvs. side, aluminum
10174390...91-95...350..........LT5, ZR1, DOHC, 32-valve,
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..........Gen.II LT1, aluminum, reverse
flow cooling, 175/68cc port volumes
10208890...94-96...265..........Gen.II, L99, 4.3 Liter V-8, cast iron, reverse flow
10215339...97......350..........Gen.III, LS1, aluminum, 68cc
10225121...94-95...350..........LT5, ZR1, DOHC, 32-valve,
drvs. side, aluminum
10225122...95......350..........LT5, ZR1, DOHC, 32-valve,
pass. side, aluminum
10239902...96-up...350..........Gen.II LT4, aluminum, reverse
flow cooling, 195cc port, 54.4cc chamber, angle plug
10239906...96-up...350.........."Vortec 5700", "L31", 64cc chamber,
170cc intake port, 1.94"/1.5" valves
12367712...99-up................"Fast Burn", aluminum, 210cc intake,
port, 2.00/1.55 valves, 62cc chamber
12367713...99-up................"Fast Burn" used on ZZ430 crate motor, aluminum, 210cc intake
port, 2.00/1.55 valves, 62cc chamber
12480005...2000.................LS1 "GTZ", 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 & plug location
12506450...87-95...350
12509859...87-94...305
12516852...87-95...350
12529742...95-96...265..........Gen.II, "L99", cast iron
12551561...96......350..........Gen.II, "LT1", aluminum
12552520...97-up...305..........Vortec, truck
12554290...94-96...350..........Gen.II, "LT1", cast iron version, used
on "9C1" Police package, Impala SS,
Cadillac Fleetwood, Buick Roadmaster
reverse flow cooling
12554291...95-96...265..........Gen.II, "L99", cast iron
12555690...96......350..........Gen.II, "LT4", aluminum
12556743...99......325..........Gen.III, 5.3L, aluminum, truck, van
12558059...97......305..........Vortec, truck, 1.84"/1.5" valves
12558062...98......350..........L31 Vortec, truck, 64cc chambers, 1.94/1.5, 170cc intake port
12558806...97-98...350..........Gen.III, "LS1", aluminum, 68cc
12559853...99-up...350..........Gen.III, "LS1", aluminum, 68cc
12559862...99-00................Gen.III, aluminum 4.8/5.3L
12559895...00-up...325..........Gen.III, aluminum, Vortec 5.3L
12561706...01-04................Gen.III, 5.3L, aluminum
12561873...99-01...364..........Gen.III, 71cc, iron
12562317...01-04...364..........Gen.III, 71cc, aluminum
12564241...00-up...350..........Gen.III, "LS1", aluminum, 68cc
12564243...01-up...350/364......Gen.III, "LS6", "LS2", aluminum
12572035...01-04...364..........Gen.III, 6.0L, aluminum, 71cc
14008856...79-81...267
14010201...82-85...305
14011034........................Bowtie, cast iron, 64cc chambers,
184cc port volume, angle plug,
"Phase II" head
14011049........................Bowtie, aluminum, 55cc chambers,
angle plug, 180cc ports, "Phase 6"
14011083...55-86...350..........Crate motor for years indicated.
285/300hp, 64cc chambers, 1.94"/1.5" valves
14014415...80-85...267/305
14014416...80-86...305..........1.84"/1.5" valves, 58cc chambers
14014440...80......305..........1.84"/1.5" valves
14019821...80-86...350
14019924...79-81...267
14019926...80-86...350
14010516...80-86...350
14020517...80......350
14020555...81......305
14020556...81......350
14022056...85......350
14022206...80......350
14022301...80-86...305
14022601...80-86...267/305......1.72"/1.5" or 1.84"/1.5" valves, 53cc chambers
14022801...80-86...305
14024816...........350..........76cc chambers, 1.94/1.5 valves, Gen.I crate motors
14034806...78-82...267
14034807...78-86...305
14034808...80-86...350
14034808...96-up...350..........76cc chambers, 1.94"/1.5" valves, Gen.I Goodwrench crate motors
14034810...80-86...350..........Truck
14034811...80-86...350..........Truck
14039121...81-86...305..........Truck
14039122...81-86...305..........Truck
14071114...80-86...350
14075381...80-86...350..........Truck
14079261...86......350
14085844...80-86...350..........Truck
14085963...86......350
14088526...........350..........Gen.II, LT1, aluminum
14089119...86-88...350
14094093...86-88...350
14096217...55-86...350..........Crate motor, 285hp/300hp, 64cc chambers,
72' or 90' center intake manifold bolt angles
14101081...87-95...305
14101083...87-up...350..........Gen.I, also used on crate motors, 285 or 300 hp, 64cc
chambers, 72' center manifold bolt
angles
14101128...86-87...350..........Aluminum, 58cc, angle plug
14102187...87-91...305..........1.84"/1.5" valves
14102191...87-up...350
14102193...87-up...305/350......1.94"/1.5" valves
22542525........................Dart/Olds/Chevy aluminum, 14'or 17' race head.
24502559...96-97................Bowtie, "SB2", 1st version,
"mirror ports", aluminum, 196cc port, CNC version 280cc port, 38cc chamber
25500141........................Buick/Chevy aluminum, 10' race head,
42cc chambers, symmetrical ports,
235cc intake port volumes,
2.1"/1.625" valves
25534351C..04-up................Gen.I Bowtie, cast iron Vortec head, 175/65cc ports, 2.00/1.55 valves, "small port head"
25534371C..04-up................Gen.I Bowtie, cast iron Vortec head, 206/77cc ports, 2.00/1.55 valves, "large port head"
33417369...90-up...350..........Gen.I Goodwrench crate motor,"Hecho en Mexico", 76cc
CASTING#.....SIZE...YEAR...MAIN CAP BOLTS....NOTES
140029.....350...80-84...2
330817.....400...72-80...2
355909.....262.....75....2
355909.....305...76-79...2
360851.....262...75-76...2...Monza V-8
361979.....305...77-79...2 or 4, some Canadian assembled heavy duty blocks have 4-bolt main caps
366245.....350...78-79...4...Bowtie
366286...................4...Bowtie, 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, two piece rear main seal.
366299...................4...Bowtie, Aluminum, nodular
iron splayed caps, wet sump,
4.00" bore
389257.....302.....67....2
393288.....283...65-67...2
460703.....350.....78....4
460776.....305...78-79...2
460777.....305...78-79...2
460778.....305...78-79...2 or 4, some Canadian assembled heavy duty truck blocks have 4-bolt main caps
471511.....267...79-82...2
3556519....283...58-61...2
3703524....265.....55....2...No oil filter
3720991....265...56-57...2
3731548....265...57......2...No side motor mounts
3731548....283...57......2...No side motor mounts
3737739....283...58-64...2
3756519....283...58-62...2
3782870....327...62-67...2
3789817....283...62-64...2
3789817....327...62-67...2
3789935....283...61-64...2
3790721....283...62-64...2...Chevy II recessed oil filter boss
3790721....327...65-66...2...Chevy II recessed oil filter boss
3791362....327...62-67...2...Chevy II recessed oil filter boss
3792563....327.....65....2
3792582....283...64-65...2
3794226....283...58-63...2
3794460....327...62-64...2
3830944....327.....63....2
3834810....283...64-66...2
3834812....283...62-63...2
3837739....283...58-62...2
3849852....283...57-66...2
3849935....283...65-67...2
3858174....327...64-67...2
3858180....327...64-67...2
3858618....350...68-76...2
3862194....283...65-67...2...Chevy II recessed oil filter boss
3862812....283...62-64...2
3892657....302.....67....2...Z-28 Camaro
3892657....327.....67....2
3892657....350.....67....2...Camaro
3896944....283...66-67...2
3896948....283...66-67...2
3903352....327.....67....2
3914636....307.....68....2
3914638....307.....68....2
3914653....307...68-73...2
3914660....327.....68....2
3914678....302.....68....2...Z-28 Camaro
3914678....327.....68....2
3914678....350.....68....2
3931174....307.....68....2...Truck
3932371....307...69-73...2
3932373....307...68-73...2
3932386....302.....69....4...Z-28 Camaro
3932386....327.....69....2
3932386....350.....69....2 or 4
3932388....327.....69....2
3932388....350.....69....2 or 4
3933180....327...68-69...2
3951509....400...70-71...4
3951509....400...74-80...2
3951511....400...70-73...4...Some replacement blocks had 2-bolt main caps
3956618....302.....69....4...Z-28 Camaro
3956618....327...68-69...2
3956618....350.....69....2 or 4
3956632....307.....69....2
3959512....327...62-67...2...Was also used for some "CE" replacement blocks
3959532....283...64......2...Used for some "CE" replacement blocks
3959538....327...........2...Chevy II recessed oil filter boss, Used for some Chevy II "CE" replacement blocks
3970010....302.....69....4...Z-28 Camaro
3970010....327.....69....2...Trucks and industrial
3970010....350...69-80...2 or 4
3970014....350...70-76...2 or 4
3970020....307...69-73...2
3970024....307...69-73...2
4715111....305.....80....2
6259425....350...69-76...2
10036033...350...........4...Goodwrench crate motor, 2-piece rear
seal, "Hecho en Mexico"
10046164...305.....86....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...350...86-up...2 or 4...one piece rear seal, some "Made in Canada"
10066036...350...........2 or 4...Target Master/Goodwrench crate motor, 2-piece rear
seal, "Hecho en Mexico"
10066038...350.....92....4...Goodwrench crate motor, 2-piece rear
seal, "Hecho en Mexico"
10090511...350.....90....2...LT-5, ZR1 Vette, 375hp
10125327...350...92-up...2 or 4...Gen.II LT-1, reverse flow cooling
10125327...350...96-up...2 or 4...Gen.II LT-4, 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...350...91-92...4...LT-5, ZR1 Vette, 375hp
10168588...265...94-96...2...L99, Gen.II, 4.3 Liter V-8, Caprice, reverse flow cooling
10199001...350...93-95...4...LT-5, ZR1 Vette, 405hp
10243878...305...96-98...2...Vortec truck, roller cam, one-piece rear seal
10243880...350...95-00...2 or 4...Vortec truck, Gen.I crate motors and "ZZ4", roller cam, one piece rear seal
12550592...350...97-up...crossbolted block, Gen.III, "LS1", aluminum
12551358.........99-up...Gen.III, 4.8L or 5.3L, cast iron, truck
12551364...364...98-04...crossbolted cast iron Gen. III, 6.0L, truck
12559378...350...99-up...crossbolted block, Gen.III, "LS1", aluminum
12559846...350...98-up...crossbolted block, Gen.III, "LS1", aluminum
12560621...350...98-up...crossbolted block, Gen.III, "LS1", aluminum
12560626...350...99-up...crossbolted block, Gen.III, "LS1", aluminum
12560629...350...99......crossbolted block, Gen.III, "LS1", aluminum
12561168...350...01-up...crossbolted block, Gen.III, "LS1", aluminum
12562174...350...98-up...crossbolted block, Gen.III, "LS1", aluminum
12568952...364...05-up...crossbolted block, Gen.III, 6.0L, aluminum, LS2
12566910...325...04-up...crossbolted block, Gen.III, 5.3L, aluminum, SSR truck
12571048...325...04-up...crossbolted block, Gen.III, 5.3L
12573581...364...98-04...crossbolted cast iron, Gen.III, 6.0L, truck
12577184...364...98-04...crossbolted cast iron, Gen.III, 6.0L, truck
12577396.........02-up...Gen.III, 4.8L or 5.3L, cast iron, truck
14010201...305...80-85...2
14010202...305...80-85...2
14010203...305...80-85...2
14010207...350...80-85...2 or 4
14010209...350...80-85...2 or 4
14010280...267...79-82...2
14011064...350...83......4
14011148...350...87-89.......Roller cam, one-piece rear seal
14016376...267...79-82...2
14016379...350...77-79...2 or 4
14016381...305...80-84...2
14016382...305...79-84...2
14016383...305...80-85...2...Truck
14079287...350...86-90.......Truck
14088526...350...87-89.......Roller cam, one-piece rear seal
14088548...350...86-88...2 or 4
14088551...305...86-87...2...one-piece rear main seal
14093627...305...87-94...2...Roller or flat tappet cam, one-piece rear seal
14093638...350...87-95...2 or 4...Roller or flat tappet cam, one-piece rear seal
14094766...305...86-up...2...One-piece rear seal
14101147...305...85-up...2
14101148...350...86-90...4...One-piece rear seal
14102058...305...87-91...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
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, crate motor 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, 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
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, 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...86-90...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
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.