closed vs open chamber big block heads, and casting#s

grumpyvette · Nov 22, 2010

According to the book, Chevrolet Big Block V-8 Interchange Manual, by Tom Currao

According to this book, the oval port intake port volumes depend on which casting number you use.
Factory GM oval port heads with 225cc intake port volumes ....w/combustion chamber volumes ...
#385206 = 97cc
3933148 = 112cc
#346236 = 113cc

Factory GM oval port heads with 240cc intake port volumes ....w/combustion chamber volumes ...
#336781 = 113cc
3999241 = 113cc
#353049 = 113cc

Factory GM oval port heads with 260cc intake port volumes ....w/combustion chamber volumes ...
#3872702 = 98cc
#3904390 = 98cc
#3909802 = 101cc
#3917215 = 101cc
#3931063 = 101cc
#3964290 = 101cc
#3993820 = 113cc
#3873702 = 96cc
#3964280 = 96cc

Factory GM rectangle port heads with 325cc intake port volumes ....w/combustion chamber volumes ...
#3904391 = 107cc
#3904392 = 107cc
#3919840 = 107cc
#3919842 = 107cc
#3946074 = 118cc
#3964291 = 108cc
#3994026 = 118cc
#6272990 = 118cc
14096188 = 118cc
OPEN CHAMBER, BOTTOM HEADS..................................................CLOSED CHAMBER UPPER HEADS IN THE PICTURE BELOW

close chamber (TOP) creates more compression and has a larger quench are due to the smaller combustion chamber but the tighter combustion chamber shrouds the valves and restricts flow in the valve curtain area.
open
chamber (bottom) has less valve shrouding and breaths better but requires a dome piston to reach the same compression ratio that the close chamber heads produce with a flat top piston, both can produce good horsepower but the open chamber breath better at higher rpms

http://www.grumpysperformance.com/p173016_image_large.jpg

http://www.grumpysperformance.com/ovalvsrectangle3.jpg
http://www.grumpysperformance.com/openchamber3.jpg

http://www.grumpysperformance.com/bbcheads2.gif
lower heads are the common newer peanut port, the upper #781 heads are standard size older design oval port heads

PEANUT PORT HEADS ABOVE MAKE GOOD LOW RPM TORQUE BUT ARE RESTRICTIVE OVER MID RPM LEVELS ON A 427 or LARGER ENGINE

many guys will tell you that selecting oval port heads is better on a street car engine, and they generally have a point, yet depending on compression ratio and cam used you may never notice any loss of low rpm torque, if you select a reasonable size rectangular port head and matched components ,this is one of the huge semi-myths about big block engines.
while its true that the low rpm torque does tend to be reduced with stock oval port heads vs stock rectangular port heads ,its also true that the compression, intake manifold, cam timing,rear gearing and header designs all change the results and its very easy to build a rectangular port engine that destroys tires, and theres a huge range in size of the ports in BOTH oval and rectangle port aftermarket heads

http://www.carcraft.com/techarticles/cc ... ewall.html

[color]read the article[/color]

Peaks and Averages
................Avg. TQ Avg. HP Peak TQ Peak HP
Iron .. ........541.1 475.0 595 .........521
Edelbrock 582.1 514.9 618 ........582
Dart .......... 584.2 517.7 615 .......595
TFS ................590.3 522.5 626 ... 595
Brodix .....590.8 ........523.0 626 ........597

336781.....73-85...oval...OPEN...454, 118cc chamber, 256/114cc ports

14092360...86-90...oval...OPEN...454 Truck, "peanut" round ports
346236.....75-87...oval...OPEN...454, 120cc chamber, 225/116cc ports

read thru this

http://maliburacing.com/patrick_budd_article.htm

BBC Engine Block Casting Numbers
Casting # Year CID Comments
340220 1972-76 427 tall truck
345014 1974-86 454 truck
346236 1974-76 454 215, 2 bolt
359070 1974-90 454 truck
361959 1973-85 454 car & truck
364776 1968-84 427 tall truck
364779 1968-88 366 tall truck
473478 1968-84 427 tall truck
3782870 1968-76 427 tall truck
3855061 1965-67 396
3855961 1966-67 396 325, 360, 2 bolt
3855962 1965-66 396 360, 375, 425, 4 bolt
3855977 1965-67 366 tall truck
3866961 1966-69 396 Chevy, Chevy truck
3869942 1966-67 427 390, 425, 2&4 bolt
3873858 1966 396 375, 4 bolt
3902406 1967 396 325, 350, 375, 2&4 bolt
3902466 1965-67 396 ??
3904351 1967 427 385, 390, 400, 425, 430, 435, 2&4 bolt
3904354 1966-67 366 tall truck
3916319 1968-85 366 tall truck
3916321 1968 427 385, 390, 400, 425, 430, 435, 2&4 bolt
3916323 1968 396 325, 350, 375, 2&4 bolt
3918319 1966-70 366 Chevy truck, GMC, tall truck
3925521 1968-85 366 tall truck
3928319 1969-73 366 GMC, tall truck
3935439 1968-69 427 335, 390, 400, 425, 430, 435, 2&4 bolt
3935440 1968-69 396 265, 325, 350, 375, 2&4 bolt
3937724 1968-85 366 tall truck
3937726 1968-84 427 tall truck
3955270 1969 427 335, 390, 400, 425, 430, 435, 2&4 bolt
3946052 1969 427 430 ZL-1, 4 bolt, aluminum
3955272 1969 396/402 265, 325, 350, 375, 2&4 bolt
3955274 1968-85 366 tall truck
3955276 1968-84 427 tall truck
3963512 1969-71 427 335, 390, 400, 425 COPO, 430, 435,
454 345, 360, 365, 390, 425, 450 2&4 bolt
3963513 1973-76 454 215
3965440 1968-69 396
3965449 1968-72 396
3965540 1968 396
3969854 1969-72 396/402 240, 265, 300, 325, 330, 350, 375,
454 360, 2&4 bolt
3969858 1968-84 427 tall truck
3999289 1972-78 454 215, 235, 240, 270, 2 bolt, car & truck
3999290 1972 402 240, 2 bolt
3999293 1968-85 366 tall truck
3999294 1968-84 427 tall truck
6272176 1968-76 366 Chevy, GMC, tall truck
6272177 1972 402 210
6272181 1973-76 427 tall truck
1401544 1975-87 454 truck

Big Block Chevy Cylinder Heads
Open vs. Closed Chamber - A good way to describe big-block heads is to categorize them as open or closed chamber. Closed-chamber cylinder heads have small combustion chamber volumes for high compression ratios, with even mildly domed pistons. Open-chamber designs are larger and provide lower compression ratios, so require a much larger piston dome to achieve the same compression as a closed-chamber head.

Use of either style head requires that the correct pistons are used, otherwise...

BBC Cylinder Head Casting Numbers
RECTANGULAR PORT - Valve size 2.19 intake, 1.88 exhaust
Casting Years CID Chamber CC HP/RPO/Comments
3904392 1967 427 Closed 106.8 430, 435 L-88/L-89, 1.72 ex
3919842 1968-69 396 375 L-89
427 Closed 106.8 430, 435 L-88/L-89, 1.84 ex
3946074 1969-71 396,402 375 L-89, 427 430 L-88/ZL-1
454 Open 118.0 425, 465 LS-6/LS-7, round ex
10051128 1990-94 454 Semi Open 72cc, IP 400cc, bowtie, sym port
14011077 1989-94 454 Open 118.0cc, IP 295cc, replacement, C port
14044861 1989-94 454 Open 425, 105.0cc, IP 380cc, bowtie, W port
3856208 1965 396 Closed 108.9 375, 425 Z-16/L-37, 1.72 ex
3873858 1966-67 396 375 L-78
427 Closed 108.9 425 L-72, 1.72 ex
3904391 1965-67 396 375 L-78
427 Closed 106.8 425, 435 L-71/L-72, 1.72 ex
3919840 1967-69 396 375 L-78, 1.72.ex
427 Closed 109.0 425, 435 L-71/L-72, 425 COPO
3964291 1969-70 396/402 375 L-78, Intake Port 325cc
427 425, 435 L-71/L-72
454 Closed 450 LS-6, 108.0cc
3964292 1970 454 Closed 450 LS-6, 109.0cc
3994025 1971 454 Open 425 LS-6, 118.0cc
3994026 1971 454 Closed 425 LS-6, 118.0cc
6258723 1971 454 Open 425
6272990 1971-94 454 Open 425, 118.0cc, IP 325cc
14096188 1987-94 454 Open 425, 118.0cc, IP 325cc, replacement
14097088 1989-94 502 Open GEN V, 118.0cc, IP 325cc, replacement

OVAL PORT - Valve size 2.06 intake, 1.72 exhaust
Casting Years CID Chamber CC HP/RPO/Comments
330864 1970-81 366/427/454 Open
330865 1970-84 366/427/454 Open
336765 1973-84 427/454 Open
336781 1973-85 454 Open 113.0cc
343771 1968-85 366/427/454 Open
343772 1976-84 366/427/454 Open
343783 1975-78 454 Open car & truck
346236 1975-87 454 Open 113.0cc
346238 1975-87 454 Open 113.0cc
353049 1970-73 402/454 Open 113.0cc
473328 1968-85 366 Open
3856206 1965-66 396 Closed 325 97.2cc
3856213 1966-70 366 Closed truck
3872702 1966 396 325, 360 L-34/L-35
427 Closed 390, L-36 98.4cc
3876875 1966-70 427 Closed truck
3904390 1966-67 396 325, 350 L-34/L-35
427 Closed 390, 400, L-36/L-68 98.4cc
3904393 1966-68 366 Closed truck
3909802 1966-67 396 325, 350 L-34/L-35
427 Closed 385, 390, 400, L-36/L-68 100.9cc
3917215 1967-69 396 325, 350 L-34/L-35
427 Closed 335, 385, 390, 400 100.9cc
3917219 1966-70 366/427 Closed truck
3931063 1969-70 396 325, 350 L-34/L-35
427 Closed 335, 385, 390, 400 100.9cc
3933148 1969 366/396 Open 2V/427 265 122.1cc car & truck
3933149 1969-70 427 Open 122.1 cc truck
3964280 1966-70 427 335, 385, 390, 400
454 Closed 345, 360, 390 LS-5
3964290 1969-70 396/402 325, 330, 350
427 335, 385,390, 400
454 Closed 345, 360, 390 LS-5 100.9cc
3965198 1969 396 truck
3975950 1968-70 366/427 Closed truck
3986133 1970-85 366/427 Closed truck
3986136 1970-84 366/427 Closed truck
3993820 1971 402 300, 330 LS-3
454 Open 365 LS-5 113.0cc
3999241 1972 402 240, 300, 330 LS-3
454 Open 365 LS-5 113.0cc
6272292 1971 402 240, LS-3
454 Open 270, LS-5
10101136 1991-94 454 Open truck
10121033 1978-88 454 Open truck
12352783 1979-93 454 Open truck
14025175 1983-93 454 Open truck
14081044 1986-90 454 Open truck
14092359 1986-89 427 Open truck
14092360 1985-89 454 Open truck
14101398 1986-90 454 Open truck

BBC Camshaft Part Numbers
Part # Year Type Lift Dur @ .050 lift Comments/Specs/RPO's/Apps
340282 Solid .560I/.560E .262I/.262E 121 deg overlap, competition-short track apps
353040 1973-74 Hyd .440I/.440E .210I/.210E production Corvette
3863143 1965-71 Solid .520I/.520E .242I/.242E See Note 1
3883986 1965-72 Hyd .460I/.488E .213I/.217E See Note 2
3904362 1965-71 Solid .520I/.520E .242I/.242E See Note 3
3925533 1965-69 Solid .540I/.560E .262I/.269E 133 deg overlap, 427 L-88, Reverse rotation
3925535 1965-69 Solid .540I/.560E .262I/.269E 133 deg overlap, 427 L-88, standard rotation
3959180 1969-70 Solid .560I/.600E .262I/.273E 135 deg overLap, 427 ZL-1, 454 LS-7
3994094 Solid .600I/.600E .286I/.286E See Note 4
6272989 Hyd .500I/.500E .222I/.221E 121 deg overlap, marine grind or HP street
14096209 Hyd .500I/.500E .222I/.221E 121 deg overlap, marine grind or HP street (6272989)

Note 1: 80 deg overlap, 396 375hp L-78/L-89, 427 425/435hp L-71/L-72, 454 450hp LS-6, HP street
Note 2: 396 325/350hp L-34/L-35, 427 385/390/400hp L-36/L-68, 454 345/360/390hp LS-4/LS-5, good torque/HP
Note 3: 80 deg overlap, 396 375hp L-78/ L-89, 427 425/435hp L-71/L-72, 454 450hp LS-6, HP street
Note 4: 148 deg overlap, maximum power with F.I. or tunnel ram, Can Am

BBC Crankshaft Part Numbers
Casting # Year CID Comments/Specs/RPO's/Apps
330570 427 truck,1053,forging number 6223
336782 1970-74 454 with automatic transmission
3879621 1967 427 L-88, See Note 1
3882841 1965-71 396 See Note 2
3882842 1965-69 427 forged, cross drilled, balanced for 11:1 CR
3882849 1966-69 427
3887114 1965 396 tufftrided, 5140
3963521 454 4 in stroke, 5140, raw forged
3963523 1970-71 454 LS-6, See Note 3
3963524 1970-71 454 LS-7, See Note 4
3965746 1965-69 430 raw forged, semi finished, 3.4-3.8 stroke
3965753 1970-72 495 raw forged, semi finished, 3.9-4.25 stroke, 5140
3967811 1968-69 427 L-88/ZL-1, See Note 5
3975945 1970 454 with manual transmission
3993804 427 raw forged, 3.75 stroke, 5140
3993878 1971-72 454 LS-6
10051169 454 raw forged, 4340, 3.75-4.25

Note 1: L-88, with 3/8 in bolt rods, balanced for 12.5:1 CR, tufftrided, cross drilled
Note 2: forged, cross drilled, 3.76 stroke, tufftrided, balanced for 11:1 CR
Note 3: 1053, tufftrided, cross drilled, balanced for 9.25:1 or 11.25:1 CR, forging number - 3520 and 7416
Note 4: 4 in stroke, HD, 5140, LS-7, balanced for 12.5:1 CR, tufftrided, cross drilled
Note 5: tufftrided, 5140, with 7/16 in bolt rods, tufftrided, cross drilled, forging number - 7115

BBC Exhaust Manifold Casting Numbers
Cast # Years Side CID Applications
329225 1973-76 LH 454
353028 1973-76 LH 454
353030 1973-76 LH 454 police
3856297 1965 LH 396 325
3856301 1965 LH 396 425 Corvette
3856302 1965 RH 396 425 Corvette
3856306 1965 RH 396 325
3857297 1965 LH 396 325
3868874 1965-66 RH 396 325, 360, 375 Z-16
3869925 1965 LH 396 375 Z-16
3872770 1966 RH 396
3880827 1966-69 LH 427/454 Corvette
3880828 1966-72 RH 427/454 Corvette
3880869 1970-72 LH 454 Corvette
3883999 1966 LH 396 325, 360, 375
3884504 1966-67 RH 396/427 325, 385, 390
3892307 1966-67 LH 396/427 325, 390
3902401 1967 LH 396
3904399 1966 LH 396
3909879 1967-70 LH 396/427 COPO/454 325, 350, 375, 425, 430
3909880 1967 RH 396 325, 350, 375
3914613 1968-70 LH 396/427 265, 325, 335, 345, 390, 425
3916178 1968-70 RH 396/427 COPO/454 325, 350, 375, 425, 430
3969869 1970-74 LH 454 Corvette
3989310 1971-72 RH 402/454
3989343 1971-72 LH 402/454
3994045 1973-75 LH 454 police

BBC Intake Manifold Casting Numbers
ALUMINUM RECTANGULAR PORT - Holley 4V
Casting Years CID HP/RPO/Config
3866963 1965 396 375, 425 L-37
3885069 1966-68 396 375 L-78
427 425 L-72
3886093 1967 427 430 L-88
3894374 1967 427 435 3x2 L-71
3894382 1967 427 400 3x2 L-68, oval port
3919849 1968 427 390 L-36, oval port, Qjet
3919850 1968 427 400 3x2 L-68, ovat port
3919852 1968 427 435 3x2 L-71
3919878 1968 396 375 L-78
427 425 L-72
3933163 1968-69 396 375 L-78/L-89
427 425 copo
3933198 1968-69 427 430 L-88/ZL-1
3937793 1968 427 390 L-36, oval port, Qjet, Late
3937795 1969 427 400 3x2 L-68, oval port
3937797 1969 427 435 3x2 L-71
3947801 1969 427 390 L-36, oval port, Qjet
3963569 1970-71 396/402 375 L-78/L-89
454 LS-6, lowrise
3967474 1971 454 425
6269318 1972 454

BBC Intake Manifold Casting Numbers
IRON OVAL PORT - Rochester Q-jet 4V
Casting Years CID HP/RPO/Config
336789 1974 454 235, 270
346242 1975 454 215
353015 1973 454 215, 245
393841 1973-75 454 215
3856289 1965-66 396 325 L-35
3866948 1966-67 396 325, 360 L-34/L-35
427 390, Holley
3883948 1966-68 396 325 L-35
427 385, 390 L-36
3931067 1969 396 325 L-35
427 335, 390 L-36
3952900 1969 396 265 2V
3955287 1970-71 402 300, 330, 350 LS-3
454 360, 365, 390
6263753 1972 402 240 LS-3
454 240, 270

grumpyvette · Nov 22, 2010

Re: closed vs open chamber big block heads

Chev Big Block V8 Engine Block Casting Numbers

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

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"
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
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.
Chev Big Block V8 Cylinder Head Casting Numbers

CASTING#.....YEAR...PORT TYPE.....ENGINE SIZE

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...86-90...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

grumpyvette · Dec 8, 2012

Ive frequently heard guys ask if they can swap the better breathing open chamber heads onto the older close chamber engine short blocks, and if the older closed chamber pistons will work with the newer open chamber heads?
the newer open chamber heads may breath better but they are also slightly more detonation prone as they have less quench area.
Id also point out that the newer port designs are frequently far superior to the older stock port designs BUT don,t think the older designs can,t be ported to flow well.
Well the truth here is that you have a great many variations,dome designs and dome heights and the fact is that youll need to get out some modeling clay and take some measurements.
obviously theres a general con sen-sis on the basic shape and generally the stock chevy heads are used as a standard, but you must check clearances on every build as theres some variation.

CLOSED CHAMBER DESIGN

OPEN CHAMBER DESIGN
sure chevy and the after market both, made several stock replacement or aftermarket open chamber heads that will work great on a 396 bbc

https://www.cartechbooks.com/techtips/killerbigblockchevy/

http://www.superchevy.com/how-to/en...206-oval-port-big-block-chevy-cylinder-heads/

http://garage.grumpysperformance.co...n-chamber-big-block-heads-and-casting-s.3960/
BBC 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....69-72...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

both the valve clearance and dome to chamber clearances vary a great deal so theres no absolute correct in every case answer.
its been my experience that the smaller height closed chamber pistons will or at least can be easily machined to clear the larger open chamber combustion chambers, but the taller closed chamber dome pistons can be a problem as theres not enough material in the hollow dome to allow the correct machining to be done.
but you need to measure because for an example a edelbrock aluminum head, doesn,t have the exact same configuration as a trickflow, AFR, or dart or brodix head , all of them vary as to the size and location of the combustion chamber to some degree. and KEITH BLACK PISTONS, don,t look the same as J&E, TRW, OR PROBE PISTONS EITHER

RELATED INFO, YOU SHOULD READ THRU

http://maliburacing.com/patrick_budd_article.htm

viewtopic.php?f=52&t=399

viewtopic.php?f=69&t=5123

viewtopic.php?f=52&t=319

Indycars · Dec 10, 2012

I took the information from the 2nd post above this one to create an
easy to read Big Block Chevy Cylinder Head reference.

BBC-Head,-Casting#,-Year,-Port,-Chamber,-Engine-1.jpg

BBC-Head,-Casting#,-Year,-Port,-Chamber,-Engine-2.jpg

BBC-Head,-Casting#,-Year,-Port,-Chamber,-Engine-3.jpg

grumpyvette · Dec 10, 2012

thanks for posting that, its much easier to read that way!

THE ZL1 aluminum block makes over 550hp when correctly tuned with minor mods and a good roller cam

THE 572 is the largest factory available big block crate engine, and in it performance version it makes over 750hp when correctly tunned with minor mods and a good roller cam

Big-Block Chevy Cylinder Head ID. Finding Swap Meet Gold

By RANDY BOLIG FEBRUARY 20, 2019

When it comes to making power, big-block Chevys are known for having an easy time making a lot of it. The abundance of cubic inches is staggering, and the canted-valve cylinder heads are largely responsible since they flow a seriously large amount of air. Let’s face it, moving air makes power, and big-block Chevy heads do that very well.

The original cylinder-head design is often referred to as a 26-degree head. This is due to one of the intake-valve angles. But 26 degrees is only one of four angles needed to actually describe the big-block’s valve positioning. In reality, the exhaust valve is tilted 17 degrees relative to the deck surface, and both the intake and exhaust valves are inclined 4-degrees laterally. These various valve angles give the big-block head a characteristic “valves pointing everywhere” appearance when the valve covers are removed. This is where the “porcupine head” nickname originates.

The cast-iron head 3856208 was used on the 1965 Corvette with the 425 hp 396ci engine, and on Z16 Chevelles. If you find a pair now, expect to pay around $3,000.

Factory big-block Chevy heads were offered in both aluminum and cast iron, both open- and closed-chamber designs, and oval (passenger car) or rectangular (high performance) intake ports. Late-model trucks with big blocks feature an even smaller oval-intake port, frequently referred to as the “peanut” port.

When the big-block head was introduced in the mid-’60s, they all had closed combustion chambers with a roughly 100 to 109cc capacity. In 1969, the open combustion chamber was introduced and offered better air/fuel flow and combustion characteristics. The chamber size was roughly 114 to 118cc.

Gen V and Gen VI big-block engines use non-adjustable rocker arms, retained by shouldered bolts. Mark IV and earlier engines use conventional threaded-studs that allow changes in valve lash. GEN V and VI heads can be converted to adjustable rockers by installing special aftermarket rocker studs, or by drilling and tapping the stud bosses for Mark IV 7/16-inch diameter rocker studs.

Most production big-block heads have similar characteristics. These include 7/16-inch rocker-arm studs (except Gen V and Gen VI) and a seven-bolt valve cover pattern. The Gen V and VI heads used a non-adjustable rocker arm with 3/8-inch studs.

While all early cast-iron and all-aluminum heads used 3/4-inch-reach gasketed spark plugs, most iron heads made after 1969 utilize smaller, taper-seat spark plugs. Aluminum heads possess two additional threaded bosses under the intake runners. This is for additional clamping and better head-gasket retention when used with blocks that have provisions in the lifter valley. The only OE blocks with these bosses were the rare ZL1 aluminum blocks, but many aftermarket blocks have this added feature. Mark IV, Gen V, and Gen VI heads all have the same head-bolt pattern, but they are not interchangeable due to different water jacket cooling passages.

Many enthusiasts have purchased a set of used heads at a swap meet, and unfortunately, ended up getting something they didn’t actually want. This is where knowledge is king. Knowing what you’re looking at can definitely save you a a lot of money – and headaches – when scouring the “used” pile. That’s why we have put together this short big-block Chevy head ID guide to help you identify that swap-meet gold.

Big-Block Chevy Cylinder Head Casting Numbers

330864: ’68 through ’84 oval port, open chamber, 2.06- and 1.72-inch valves. Used on 396ci, 402ci, 366ci truck, 427ci truck, and 454ci truck.

330865: ’68 through ’84 oval port, open chamber, 2.06- and 1.72-inch valves. Used on 396ci, 402ci, 366ci truck, 427ci truck, and 454ci truck.

330866: ’68 through ’78 oval port, open chamber, 2.06- and 1.72-inch valves. Used on 366ci truck and 427ci truck.

330867: ’68 through ’73 oval port, open chamber, 2.06- and 1.72-inch valves. Used on 427ci truck.

336765: ’68 through ’78 oval port, open chamber, 2.06- and 1.72-inch valves. Used on 427ci truck.

336768: ’73 through ’76 oval port, open chamber, 2.06- and 1.72-inch valves. Used on 427ci truck.

336781: ’73 through ’85 oval port, open chambers, 2.06- and 1.72-inch valves. Used on 454ci engines.

343771: ’68 through ’86 oval port, open chamber, 2.06- and 1.72-inch valves. Used on 366ci truck, 427ci truck, and 454ci engines.

343772: ’68 through ’86 oval port, open chamber, 2.06- and 1.72-inch valves. Used on 366ci truck, 427ci truck, and 454ci engines.

343783: ‘70 through ’76 oval port, 2.06- and 1.72-inch valves. Used on 454ci truck engines.

346236: ’75 through ’87 oval port, open chamber, 2.06- and 1.72-inch valves. Used on 454ci engine.

352625: ’70 through ’76 oval port, open chamber, 2.06- and 1.72-inch valves. Used on 454ci Truck.

353049: ’73 through ’84 oval port, open chamber, 2.06- and 1.72-inch valves. Used on 454ci engines.

366765: ’74 through ’78 oval port, open chamber, 2.06- and 1.72-inch valves. Used on 427ci truck.

473328: ’68 through ’69 oval port, open chamber, 2.06- and 1.72-inch valves. 366ci truck.

3856206: ’65 and ’66 oval port, closed chamber, 2.19- and 1.88-inch valves. Used on 396ci engines. 97cc chamber.

3856208: ’65 rectangular port, closed chamber, 2.19- and 1.99-inch valves. Used on 396/425 hp, 396/375 hp Z-16 Chevelle.

3856213: ’66 through ’82 oval port, closed chamber, 2.19- and 1.88-inch valves. Used on 366ci, and 427ci trucks.

3856260: ’68 oval port, closed chamber, 2.19- and 1.88-inch valves. Used on 396ci truck.

Aluminum heads with casting number 3919842 were factory cylinder heads for L89 and L88 engines. Expect to pay a lot of money if you even find a usable pair.

3872702: ’65 and ‘66 oval port, closed chamber, 2.19- and 1.88-inch valves. Used on 396ci and 427ci engines.

3873858: ’65 through ’67 rectangular port, closed chamber, 2.19- and 1.88-inch valves. Used on 396ci and 427ci engines.

3876875: ’77 through ‘85 oval port, open chamber, 2.19- and 1.88-inch valves. Used on 427ci truck.

3904390: ’67 oval port, closed chamber, 2.19- and 1.88-inch valves. Used on 396ci and 427ci engines.

3904391: ’67 rectangular port, closed chamber, 2.19- and 1.88-inch valves. Used on 396ci and 427ci engines.

3904392: ’67 rectangular port, closed chamber, 2.19- and 1.88-inch valves, aluminum. Used on 427ci L88 and L89 engines.

3904393: ’68 through ’76 oval port, open chamber, 2.19- and 1.88-inch valves. Used on 366ci truck.

3908952: ’67 oval port, open chamber, 2.19- and 1.88-inch valves. Used on 427ci truck and marine engines.

3909802: ’67 oval port, closed chamber, 2.19- and 1.88-inch valves. Used on 396ci and 427ci engines.

3917215: ’67 and ’68 oval port, closed chamber, 2.19- and 1.88-inch valves. Used on 396ci and 427ci engines.

3917219: ’68 through ’85 oval port, open chamber, 2.06- and 1.72-inch valves. Used on 366ci and 427ci truck engines.

3919840: ’67 through ’69 rectangular port, closed chamber, 2.19- and 1.88-inch valves. Used on 396ci and 427ci engines.

3919842: ’68 and ’69 rectangular port, closed chamber, 2.19- and 1.88-inch valves, aluminum. Used on 396ci and 427ci L88 and L89 engines.

3931063: ’68 and ’69 oval port, closed chamber, 2.19- and 1.88-inch valves. Used on 396ci, 402ci, and 427ci engines.

3933148: ’69 through ’84 oval port, open chamber, 2.06- and 1.72-inch valves. Used on 396/265 hp, 366ci and 427ci truck engines.

3933149: ’68 through ’76 oval port, open chamber, 2.06- and 1.72-inch valves. Used on 427ci truck.

3935401: ’68 through ’76 oval port, open chamber, 2.06- and 1.72-inch valves. Used on 427ci truck.

3946074: ’69 rectangular port, open chamber, 2.19- and 1.88-inch valves, aluminum. Used on 427ci L88 and ZL1 engines.

3946074: ’71 rectangular port, open chamber, 2.19- and 1.88-inch valves, aluminum. Used on 454ci LS6 engines.

3964290: ’69 and ’70 oval port, closed chamber, 2.06- and 1.72-inch valves. Used on 396ci, 402ci, 427ci, and 454ci engines.

3964291: ’69 through ’72 rectangular port, closed chamber, 2.19- and 1.88-inch valves. Used on 396ci, 402ci, 427ci, and 454ci engines. Could have either large- or small-hex spark plugs. Also used on crate engines after 1970.

With the casting number 3904392, this aluminum head was used on 1967 L88 and L89 engines. The "snowflake" denotes it was cast at the Winters foundry.

3965198: ’68 and ’69 oval port, closed chamber, 2.06- and 1.72-inch valves. Used on 396ci truck engines.

3975950: ’68 through ’70 oval port, open chamber, 2.06- and 1.72-inch valves. Used on 396ci (car), 402ci, 366ci, and 427ci (truck).

3986133: ’68 through ’85 oval port, open chamber, 2.06- and 1.72-inch valves. Used on 366ci, 427ci, and 454ci truck.

3986135: ’69 through ’73 oval port, open chamber, 2.06- and 1.72-inch valves. Used on 366ci and 427ci truck.

3986136: ’68 through ’84 oval port, open chamber, 2.06- and 1.72-inch valves. Used on 366ci, 427ci, and 454ci truck.

3993820: ’71 oval port, open chamber, 2.19- and 1.88-inch valves. Used on 402ci engine.

3993820: ’71 through ’84 oval port, open chamber, 2.19- and 1.88-inch valves. 454ci (car and truck)

3994026: ’71 rectangular port, open chamber, 2.19- and 1.88-inch valves. Used on 454ci LS6 engine.

3999241: ’72 oval port, open chamber, 2.06- and 1.72-inch valves. Used on 402ci and 454ci engines.

6272292: ’70 through ’78 oval port, open chamber, 2.06- and 1.72-inch valves. Used on 402ci and 454ci engines.

6272990: ’70 and later rectangle port, open chamber, 2.06- and 1.72-inch valves. Used on 454ci service replacement, and some Mark IV crate engines.

10052902: Oval port, open chamber, 206- and 172-inch valves. Mark IV crate engine and 427ci truck.

10101140: ’91 and later oval port, closed chamber, 2.06- and 1.72-inch valves. Used on 366ci and 427ci truck.

10114156: ’91 and later oval port, open chamber, 2.06- and 1.72-inch valves. Used on Gen V and Gen VI 454ci engines.

10141279: ’96 and later oval port, closed chamber, 2.06- and 1.72-inch valves. Also known as a Vortec 7400.

Casting number 10141279 is for a ’96 and later engine. These are also known as Vortec heads. They also use non-adjustable rocker arms.

10487052: ’77 through ’90 oval port, open chamber, 2.06- and 1.72-inch valves. Used on 366ci truck.

12363391: ’96 and later oval port, open chamber, 2.19- and 1.88-inch valves, aluminum, “Bow Tie” head. Fits Mark IV, Gen V, and Gen VI.

12363401: ’96 and later rectangular port, open chamber, 2.19- and 1.88-inch valves, aluminum, “Bow Tie” head. Fits Mark IV, Gen V, and Gen VI.

12558162: ’01 and later oval port, closed chamber, 2.06- and 1.72-inch valves. Gen VII “Vortec 8100” truck.

12560241: ’98 and later oval port, closed chamber, 2.06- and 1.72-inch valves. “Vortec 7400″.

12562932: ’91 through ’95 oval port, open chamber, 2.06- and 1.72-inch valves. Used on Gen V truck crate engine.

12562933: ’91 through ’95 oval port, open chamber, 2.06- and 1.72-inch valves. Used on Gen V engines.

12562934: ’00 and later rectangular port, open chamber, 2.06- and 1.72-inch valves. Used on Gen VI 502ci marine engines.

14011077: ’69 and later rectangular port, open chamber, 2.06- and 1.72-inch valves, aluminum. Used on Mark IV engines.

14044861: ’84 through ’96 rectangle port, open chamber, 2.19- and 1.88-inch valves. “Bow Tie,” aluminum, Mark IV. These are a “first design” with raised runners and a 105cc chamber.

14044861: ’96 and later rectangular port, open chamber, 2.19- and 1.88-inch valves. “Bow Tie,” aluminum. Fits Mark IV, Gen V, and Gen VI. These are a second design with raised runners and a 115cc chamber.

14081045: ’78 through ’87 oval port, open chamber, 2.06- and 1.72-inch valves. Used on 454ci engines.

14081052: ’85 through ’87 oval port, open chamber, 2.06- and 1.72-inch valves. Used on 366ci, 427ci, and 454ci truck. Marked Hi Perf.

14092359: ’86 through ’90 oval port, open chamber, 2.06- and 1.72-inch valves. Used on 366ci and 427ci truck. Marked “Hi Perf”

14092360: ’86 through ’90 oval port, open chamber, 2.06- and 1.72-inch valves. Used on 454ci truck.

14096188: ’70 through ’71 oval port, open chamber, 2.06- and 1.72-inch valves. Used on 454ci service replacement and later Mark IV LS-6, LS-7, and 454ci HO crate engines.

14097088: ’91 and later oval port, open chamber, 2.06- and 1.72-inch valves. Used on Gen V 454ci and 502ci HO.

Willem · Mar 19, 2019

I have a 1973 Chevy Suburban 454ci with 1969 366/396 Open 2V/427 265 122.1cc car & truck
OVAL PORT - Valve size 2.06 intake, 1.72 exhaust
casting number 3933148 cilinderheads.
I can’t find the right fit spark plugs for them. Can anyone help me out please?

Grumpy · Mar 19, 2019

my book shows
Champion RN14PMC
but I would take an old plug you have down to a local auto parts and have them match the thread and seat type,
as the spark plugs changed from the older 13/16 to the newer 5/8" in the late 1960s-1970 or so, Ive seen a few parts books with errors in info.
if you don,t have a plug Id suggest taking a few accurate measurements on threads and a picture of the seat
I'd certainly grab a spark plug thread chaser and determine the thread size as a first step
http://garage.grumpysperformance.com/index.php?threads/spark-plug-info.202/

most cell phones can do that picture

Willem · Mar 19, 2019

Cool. I have some with the right thread, however they won’t go in completely.
They leave some space from the seat of the cil.head to the seat of the spark plug. I bought the heads without any sparkplug in them. I’ll go with the ones your book says.
Thanks for the info. I’ll keep you posted

Willem · Mar 20, 2019

Found the rn14pmc at Rockauto.
I’m buying them there.
I’ll let you know if they are the right ones

Grumpy · Mar 20, 2019

great! ,its always good to get constructive feed back, right or wrong ,
its good to get the facts from a guy with his hands on the parts!

Complete Cylinder Heads Guide for Big-Block Chevy Engines

Induction Systems for Building Big-Block Chevy Engines - Covers how to build 396 to 572 ci Chevy Big-Block Engines Step-by-Step
www.cartechbooks.com

as with most technology, there's a rapid ongoing improvement in what parts are available,
what the components can accomplish, what other matched parts must be used, and as usual the cost is always going upwards.

closed vs open chamber big block heads, and casting#s

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Complete Cylinder Heads Guide for Big-Block Chevy Engines

closed vs open chamber big block heads, and casting#s

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Complete Cylinder Heads Guide for Big-Block Chevy Engines​

Complete Cylinder Heads Guide for Big-Block Chevy Engines