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Chevy Small Block General Information

General Information & Notes
Body Styles:
A = Chevelle/El Camino , B = Caprice (Full Size), G = Monte Carlo, F = Camaro, H = Vega/Monza
C/K = TRUCK, X = Nova/Chevy II, Y = Corvette

Crankshafts
General Crankshaft Info
All crankshafts have a casting number located on one of the rough finished throws or counterweights towards the front of the crank.

Two types of crankshafts are offered, cast nodular iron and forged steel. Since forged cranks are more expensive to produce, they are generally used only in high performance or severe duty (truck) applications.

Forged crankshafts are easily identified vs cast because a forged crank will have a wide parting line running down the length of the crank, while the cast crank has a thin parting line. Some forged cranks are tufftrided, which is a chemical heat treating process that hardens the bearing journal surfaces. When a crank is tufftrided it will have a dull grey color to it. Many cranks used in severe applications are cross-drilled, which helps ensure constant oiling to the main bearings. All tufftrided cranks are cross-drilled. Not all cross-drilled cranks are tufftrided.

Rear Main Seal
Beginning in 1986 all production small block chevy engines used a 1 piece rear main seal. This means the bolt pattern on the end of the crankshaft was reduced to 3.00".

Journal Size
Journal sizes were increased in 1968.
Rod Main Displacements
Small Journal 2.00" 2.30" 265, 283, 302, 327
Large Journal 2.10" 2.450" 262, 267, 302, 305, 307, 327, 350
400 Crank 2.10" 2.650" 400

Crank stroke
262ci / 3.100", 265ci / 3.000", 267ci / 3.484", 283ci / 3.000", 302ci / 3.000"
305ci / 3.484", 307ci / 3.250", 327ci / 3.250", 350ci / 3.484", 400ci / 3.750"

Small Block Crankshaft Casting Numbers
Years Casting CID Material Journal Rmain Seal Applications
1968-73 1130 307,327 cast large two all
1968-76 1181 350 cast large two all
2680 327 steel small two
2690 350 steel two
1968-69 3279 302 forged large two Z-28
1962-67 4577 327 forged small two -
1968-73 4672 307,327 cast large two -
1975-85 310514 350 - large two -
330550 350 steel two
1975-76 354431 262 cast large two Monza,Nova
1955-67 3727449 265,283 forged small two -
3729449 265 steel two
1962-67 3734627 327 forged small two -
1955-67 3735236 265,283 forged small two -
1957-63 3735263 283 forged small two -
1962-67 3782680 327 forged small two -
3814671 327 steel small two
1955-67 3815822 265,283 forged small two -
1957-65 3835236 283 forged small two -
1956-63 3836266 265,283 forged small two -
1963-67 3849847 283 cast small two -
1964-67 3876764 283 cast small two -
1964-67 3876768 283 cast small two -
3884577 327 steel small two
1967-76 3892690 350 cast large two -
1968-73 3911001 307,327 cast large two -
3911011 307,327 cast large two
3914672 327 steel large two
3923279 302 steel large two
1969-85 3932442 305,350 cast large two in 1979-82 267
1968-73 3941174 307,327 cast large two -
1968-69 3941178 302 forged large two Z-28
1969-85 3941182 350 forged large two Z28, Vette,truck, some nitrided
3941188 350 steel two
1964-67 3949847 283 - small two
3951130 327 steel large two
1970-80 3951529 400 cast XL mns two 3.76" stroke, ext. bal.
1986-on 14088526 305,350 cast large one
1986-on 14088532 350 forged - one truck
1986-on 14088535 305,350 cast large one all
86-88 14088552 350 forged one

Pistons
GM P/N ENGINE CR/Chamber CC Dome Type Pin Type Material Usage
12514101 350 8.5:1/76cc Dish P Cast 350/190HP
- 9.1:1/64cc - - - 350/285HP
- - - - - Crate motor
12361371 350 9.1:1/64cc Dish P Cast 350/300HP Crate motor
10104455 350 9.8:1/58cc Flat top P Hyper ZZZ 1St design Crate motor
10181389 350 9.8:1/58cc Flat top P Hyper ZZZ 2nd design Crate motor
12520264 350 9.1:1/64cc Flat top P Cast 350/300HP
3946876 302 11.0:1/64cc Dome F Forged '68 to '69 Z-28
3942543 350 11.0:1/64cc Dome P Forged '69 L46
474192 350 9.0:1/76cc Dish P Cast 350 L82
3989051 350 11.0:1/64cc Dome P Forged '70 LT1
14011020 350 12.5:1/64cc Dome F Forged Heavy-Duty/NOTE 1
14011021 350 12.5:1/64cc Dome F Forged Heavy-Duty/NOTE 2
14011026 350 12.5:1/64cc Dome F Forged Heavy-Duty/NOTE 3
14011027 350 12.5:1/64cc Dome F Forged Heavy-Duty/NOTE 4

P= Pressed-on pin; F= Floating pin., Hyper = Hypereutectic
Part numbers are for standard (Std.) bore sizes.
NOTE 1: use with 5.7" rod in cylinders 2, 3, 6, 7.
NOTE 2: use with 5.7" rod in cylinders 1, 4, 5, 8.
NOTE 3: use with 6.0" rod in cylinders 2, 3, 6, 7.
NOTE 4: use with 6.0" rod in cylinders 1, 4, 5, 8.

Intake Manifolds
Years Casting CID bbls Material Carb Application
1974-76 340261 350 4 iron Q-jet A B F X/160,185,195,245,250HP
1973-81 340266 305,350 2 iron - A B F G
1982-85 340281 305,350 4 iron Q-jet B F
1976-82 346249 305,350 4 iron Q-jet all/155,165,205HP
1976-82 346250 305,350 4 iron Q-jet all
1973-77 346260 305,350 2 iron - A B F
1978-80 373598 305 2 al - G
1976-82 458520 305,350 4 al Q-jet all
1980-82 1403372 305,350 TTBI al cross-fire F Y
1955 3704790 265 2 iron - B
1955 3711348 265 4 iron - B Y
1956 3728725 265 8 al WCFB Y/225hp, 1st design
1986-57 3731394 283 8 al WCFB Y/225hp, 2nd design
1957 3731398 283 4 iron WCFB, 4jet B Y
1957 3732880 265,283 2 iron - B
1956 3735444 265 2 iron - B
1956 3735448 265 4 iron Qjet Y /210hp
1956 3737109 265 4 iron - B
1957 3739653 283 8 al - Y /245,270HP
1957 3741193 283 FI al - B
1957 3746826 265,283 2 iron - B
1958-61 3746829 283 4 iron WCFB, Qjet B Y/230hp
1962-63 3783244 327 4 iron WCFB, Qjet B Y/250hp
1963 3794129 327 4 al AFB Y 340hp
1962 3795397 327 4 iron AFB Y 340hp
1972 3797771 350 4 iron - A B F
1962-64 3799349 327 4 iron AFB B Y/300hp
1963-65 3826810 327 FI - - Y
1956-57 3837109 265,283 4 iron WCFB, Qjet B Y/210hp
1964-65 3840905 283 2 iron - A B X C K
1964-65 3844457 327 4 iron WCFB, Qjet A B X Y/250hp, Srvc repl.
1963-65 3844459 327 4 iron AFB A B X Y/300hp, srvc repl.
1964-65 3844461 327 4 al Holley Y/350,360hp
1962-65 3866922 283,327 4 iron Qjet A B X/220hp/250hp, marine use
1966-67 3872783 327 4 iron Holley A B X/275hp, w/o AIR, srvc. repl.
1966 3875954 327 4 iron Qjet A B X/275hp, w/AIR
1965 3877652 283,327 2 iron - A B C K,trk
1966-67 3877656 327 4 al Holley 350hp Hirise
1966 3882858 283 4 iron Qjet A B X/220hp
1966-67 3890490 327 4 al Holley X Y/350hp hirise
1966-68 3905393 327 4 iron Q-jet A B F X/275hp
1967-68 3910601 327 2 - - A F X
1969-70 3916313 307,350 2 - - all
1967-68 3917610 302 4 al Holley Z-28, F, hirise
1968 3919801 307,327 2 iron - A B C X
1967-68 3919803 327,350 4 iron Qjet A B F X Y/250,275,325,350HP
1969 3927183 307,327 2 iron - A B F X
1969 3927184 350 4 iron Qjet A B F X Y/255,300,350HP, srv. rep.
1969 3932472 302 4 al Holley Z-28, F, Hirise
1967-69 3941126 302 8 al Holley Z28 X ram (bottom) released to race teams in '67 w/o casting#
1967-69 3941130 302 8 al Holley Z28 X ram (top) released to race teams in '67 w/o casting#, did have Winter Foundry 'snowflake" logo.
1969-70 3958622 307,327 2 iron
1969-70 3958626 350 2 iron
1971-72 3959594 350 4 al Holley Y, Z28, LT1, Hirise, 330/255hp
1970 3965577 350 4 iron Qjet B F X/300,350hp
1970 3972110 350 4 al Holley Y, Z28, LT1 360,370hp, Hirise
1970 3972114 350 4 al Z-28, F
3972116 350 4 al Holley hirise, service repl for '70 LT1
1971 3972361 350 4 al Holley Z-28, F
1969-71 3973465 307,327 2 - - A B F X
1971 3973469 350 4 iron Qjet B F Y/270hp
1969-70 3987361 350 - iron -
1971 3990948 350 - iron -
1973 3991004 350 - iron -
1971 3991005 307 iron
1973 3997770 350 4
1973 3997771 350 4 iron Qjet all/175,190,245,250hp
1973 3997772 307 - iron -
1972 6262928 350 - iron -
6262930 - iron Y
1972 6262932 350 iron -
1971-72 350 4 iron -
1972 6263751 350 4 iron Qjet all, 175,200hp
1973 6271060 350 - iron
1957 7014360 283 FI al -
1957 7014520 283 FI al -
1957-58 7014800 283 FI al -
1958-59 7014900 283 FI al -
1958 7014960 283 FI al -
1959-61 7017200 283 FI al
1959-60 7017250 283 FI al
1959-60 7017300 283 FI al
1960-61 7017310 283 FI al
1960 7017320 283 FI al
1962 7017355 327 FI al
1962 7017360 327 FI al -
1962-63 7017375 327 FI al -
1964-65 7017380 327 FI al -
1979-80 14007374 305 2 al -
1981 14014432 350 4 al -
1978-85 14057053 305,350 4 al Qjet Pass, Camaro, Truck

Exhaust Manifolds
FY LY Casting CID Applications
1973 76 336709 350 F
1973 75 336710 307,350,400 A B F G
1973 80 346222 307,350,400 A B F G
1975 77 346247 350 A B F G
1975 77 346248 350 A B F G
1976 80 364753 305,350,400 all
1970 82 372243 350 Y
1978 82 462697 267,305 G
1978 82 462698 267,305 G
1955 - 3704791 265 B Y
1955 - 3704792 265 B Y
1956 - 3725563 265 B Y
1956 - 3731557 265 B Y
1956 - 3731558 265 B Y
1957 - 3733975 283 B Y
1957 - 3733976 283 B Y
1965 - 3746563 327 Y
1962 68 3747038 283,327 B Y
1958 67 3747042 283 B Y
1964 - 3747938 327
1964 - 3747942 327
1958 63 3749965 283,327 B Y
1958 65 3750556 283,327 B Y
1964 67 3790729 283,327 Chevy II
1965 - 3790730 283,327 Chevy II
1965 - 3791162 283,327 Chevy II
1966 67 3791182 283,327 B
1962 63 3797901 327 Vette
1962 65 3797902 327 Vette
1963 - 3797942 327 Vette
1967 68 3834947 283,327 B
1955 - 3836968 265 B
1955 3837069 265 Y
1964 - 3840715 283,327 A
1964 68 3840912 all A F X
1964 71 3846559 327,350 Vette
1964 65 3846563 327 Vette
1964 67 3849288 283,327 Chevy II
1964 67 3849290 283,327 Chevy II
1964 68 3855163 283,327 B C K
1966 67 3872723 283,327 Chevy II
1966 - 3872729 283,327 A
1967 68 3872730 all A F
1966 67 3872738 283,327 Chevy II
1966 68 3872741 283,327 B
1967 71 3872765 327,350 Vette
1966 68 3872778 283,307,327 B C K Y
1964 67 3890424 283,327 Chevy II
1967 - 3892679 all A F X
1967 68 3892683 all A F
1966 68 3893604 283,327 B
1967 - 3893608 all A F
1967 68 3896956 283,307,327 C K
1967 68 3905364 307,350,400 C K
1969 70 3932376 307,350 A F
1970 72 3932461 350 Vette
1969 70 3932465 327,350 B
1969 70 3932469 350,400 B
1969 70 3932473 307,350 B
1969 - 3932481 350 Y
1967 - 3940972 350 F
1969 71 3942527 302,307,350 A F X
1969 70 3942529 307,350 A F X
1969 - 3946826 302,307,350 A F X
1969 - 3946826 302
1972 73 3959562 307,350 A F
1971 72 3973432 307,350 A B F X
1972 74 3986330 307,350 F
1970 72 3989036 350,400 B Y
1969 73 3989041 302,307,350 A F X
1970 73 3989043 307,350 A B F X

Balancer & Flywheel
FLYWHEELS
Part # DIA. Teeth Comments
3991469 14" 168 two-piece seal, internally balanced
3986394 14" 168 400 External balance, two-piece seal
10105832 14" 168 86-later, one-piece rear seal, ext. balance
14085720 12.75" 153 Lightweight (15 lbs.), nodular iron, two-piece seal, int bal
14088646 12.75" 153 86-up, Lightweight (15 lbs.), nodular iron, one-piece rear seal, ext bal
14088648 14" 168 86-up, one-piece rear seal, ext. balance
14088650 12.75" 153 86-up, one-piece rear seal, ext balance
10174482 89-up with six-speed m/t, requires starter (10455709)
Common clutch sizes are: 10.4", 11.0", and 11.85". Some flywheels are drilled for two different clutch patterns.

FLEXPLATES
Part # DIA. Teeth Comments
471529 12.75" 153 Two-piece seal blocks, int balance
471578 14" 168 400 ext. bal, two-piece rear seal
471598 14" 168 Two-piece seal blocks, internal balance
10128412 12.75" 153 86-up, one-piece rear seal ext. balance
10128413 14" 168 86-up, one-piece seal, extra thick, HD, ext bal
10128414 14" 168 86-96, one-piece rear seal, ext. balance
14088761 14" 168 89-up 350 HO, one-piece rear seal, ext. bal.
14088765 12.75" 153 86-up, one-piece rear seal, ext. bal.
14088767 14" 168 89-up 350 HO, one-piece rear seal, HD, ext. bal

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