Corvanatics banner

Quick Links:


Corvair 95 Code Compendium

The codes and accompanying information have been acquired from a variety of authoritative sources and GM documents. The abbreviations "AM" and "P&A" identify information from Corvair 95 Assembly Manuals and GM Parts and Accessory manuals, respectively. An asterisk(*) marks parts for which there are original GM engineering drawings or other engineering documents. This analysis has resulted in some new interpretations of part histories and occasional corrections to earlier documents.

Navigation links


Patterns, Castings vs Machined Parts - Codes, Numbers and Dates
- click on image to enlarge
Patterns and Castings Several of the powertrain components were, or incorporated, parts made in a foundry. Some were cast in steel (transmission and differential cases, exhaust manifolds), others in aluminum (engine blocks, heads, and rear housing), and carried codes, part numbers and/or dates of manufacture. To make these components, molds were created by packing sand around a pattern (prototype) of the part to be produced. Each component was embossed with a unique part number, but there were multiple copies of the pattern (to maximize production rate), and each pattern carried a unique identifier, such as GM1, GM2, GM3, etc. Thus, there would be no difference between components with different pattern numbers but the same part number. Additionally, each casting was embossed with a casting date.

Casting dates - In the casting date, the month is identified by a letter

A = Jan, B = Feb, C = Mar, D = Apr, E = May, F = Jun,
G = Jul, H = Aug, I = Sep, J = Oct, K = Nov, L = Dec
The month is followed by the day, and then a single digit for the year.

The codes themselves were on embossed plates screwed to the pattern, allowing the date code to be changed day to day. The shape of the screw heads on either side of the date code signifies which shift poured the casting: 1st shift with two flat-head, 3rd shift with two round-head screws, and 2nd shift with one of each.

Machined parts A cast usually was subsequently machined to the final specifications; and the same pattern could yield different final forms, each with its own machined part number. These are the part numbers usually found in the Parts and Accessories catalogs (but not on the part itself). The machined parts were engraved with production codes and dates, which are decribed below.



Engine Codes
Where to find the ID codes- click on image to enlarge

Engine codes are located on the rear of the egine block, visible below the fuel pumptransmission code

These codes consist of a Source code followed by the assembly month and day, followed by an Engine code engine part


1961 Engines- standard 80 HP engine was only option
code Part # Application
V 3795113 manual transmission
VA 3795117 manual transmission and RPO 225 (export, low compression)
VB¥ 3814451 manual transmission and COPO 2478 (prototype A/C)
W 3795115 RPO 667 (powerglide transmission)
WA 3795119 RPO 667 and RPO 225
WB¥ ? RPO 667 and COPO 2478
¥A prototype A/C unit was under development in 1961 and appears to have been initiated as COPO 2478 and intended as a mid-1962 release as FAO 136. The engines were given codes of VB and WB. Two of the engines were produced in 1961, although production in 1962 is unknown. Documents for 1962 refer to the option either as COPO or FAO (and as "VD" in one case), possibly reflecting progress (or some indecision) as it moved toward release. Howwever it was cancelled, likely due to cost and inability to cool the large interior FC volume.

1962 Engines - standard 80 HP engine was only option
code Part # Application
V3819933manual transmission
VA3819969 manual transmission and RPO 225 (export, low compression)
VB¥3819511 manual transmission and FAO 136 (with prototype A/C)
VD¥3820191 manual transmission with COPO 2478 (with prototype A/C)
W3819967 RPO 667 (powerglide transmission)
WA3819971 RPO 667 and RPO 225
WB*3819513 667 and FAO 136
¥ See notes with 1961 codes.
1963 Engines - standard engine was 80 HP;
102 HP engine was COPO (Central Office Production Option) 9552
Code Part # Application
V3821809 manual transmission
VA3821823manual transmission and RPO L90 (export, low compression)
VD¥3834724COPO 9552A (102 HP engine with manual transmission)
VE3839393COPO 9552B (102 HP engine with manual transmission and HD clutch)
W3821815 RPO M35 (powerglide transmission)
WA3821825with RPO L90 and RPO M35
WC3841999 COPO 9552C (102 HP engine with RPO M35)
¥The best discussion of the COPO 102 HP FC engine is found in the article by Dave Newell in the 2018 CORSA Communique 39(9).
1964 Engines - standard engine was 95 HP; 110 HP engine was RPO L62
Code Part # Application
V3851815 95 HP with manual transmission
VA385181795 HP with manual transmission and RPO L90 (export, low compression)
VB3851335 110 HP engine with manual transmission
W381708595 HP with RPO M35 (powerglide transmission)
WA381708995 HP with RPO M35 and RPO L90
WB3851339 110 HP engine with RPO M35
1965 Engines - standard engine was 95 HP; 110 HP engine was RPO L62
Code Part # Application
RS 387441995 HP with manual transmission
RV 387441395 HP with powerglide
RX ? 110 HP and manual transmission
RU ? 110 HP and powerglide



Transmissions
Where to find the ID codes - click on image to enlarge

On '61 & '62 MTs the ID code is on the differential mounting boss, upper left side transmission code

On '63 - '65 MTs the ID code is on boss, lower left sidetransmission code

On '61 - '65 PGs the ID code is on the right hand side of casting and middle pan mounting boss.transmission code

'61 MT codes include the type code and assembly month and day.transmission code

'63 - '65 MT codes include type code and assembly month and day. transmission code

Codes of PG transmissions have the type code and the assembly, month, day and shift (D=day or N=night)transmission code

Transmission Sources: MTs from Saginaw; PG from Toledo

Some other distinquishing features

A backup light was never used in the FC, the hole in the case for the switch was usually drilled but plugged, as in this transmission. transmission code

In 1964 the lube drain hole (red circle) was eliminated from the 4-speed transmission. The green circle is the differential drain hole. transmission code


1961 Transmissions
Code Application Part # Case # Gear ratio, notes, etc.
ST 3 Speed MT
The standard equipment 3 speed manual transmission was the only transmissions to have a large, stamped steel access panel on the top.
3785446 3784344
1st-3.50 2nd-1.99 3rd-1.00 rev-3.97
(1961 AM)
SF 4 Speed MT
See table below for detailed descriptions of 4 speed transmissions
  3785452*
(early)
3782978* 1st-4.26   2nd-2.35  3rd-1.48   4th-1.00 rev-4.27
3785452 - was the "1st design" '61 4sp transmission. It's identified in the earliest P&A catalogs and the engineering documents indicate it to have a 4.26 1st gear; changes to the engineering document correspond with those described in Technical Service Bulletin #690.
3788154*
(late)
3788155 1st-3.65, 2nd-2.35, 3rd-1.44, 4th-1.00, rev-3.66
3788154 - was the "2nd design" '61 - early '62 4sp. This is the part number given in both the '61 and '62 assembly manuals. It has the 3.65 1st gear. This transmission was originally used for the passenger car only and was then used in the FC also, as reflected in the usage shown in the '61and '62 P&A catalogs.
BPowerglide
Powerglide transmissions were delivered to the assembly line under a transaxle part number (as a transmission + differential assembly).¥
3795640 transaxle assembly (1961 AM); 3788375= transmission (P&A 616-1 12/1960)
¥Manual transmissions and differentials were shipped directly from their sources to the assembly lines in Flint and St Louis. However, powerglide rear axles from Buffalo went first to Toledo to be mated with powerglide transmissions and converters so that they could be tested and the converter balanced. Only then were the complete assembly units shipped to the assembly lines.

1962 Transmissions
Code Application Part # Case # Gear ratio, notes, etc.
ST 3 Speed MT¥
In order to raise the level of the lubrication in the transmission, the lube filler hole was to be moved upward 1" as a running change was implemented in January 1962. The hole diameter also would be increased from ½" to 78". Until modified parts were available, '62 FCs with the 3784344 case would receive a 45O "L" tube extension (444058) at the fill tube hole (1962 AM, Central Office Advanced Information Notice A.I. 62-13; 3/12/62)
  3826177 3784344 3.50, 1.99, 1.00 rev-3.97
SF 4 Speed MT¥
See table below for detailed descriptions of 4 speed transmissions
 3788154*
early
3788155 3788154 was continued from previous year
3799363*
late
3799364 3799363 superceded 3788154 and was used for the remainder of '62 through '63. (P&A 621A 10/61)
BPowerglide
As explained for 1961, powerglide transmissions were delivered to the assembly line under a complete transaxle assembly.
3745640 = transaxle assembly 3788375 = transmission (P&A 34 Oct '62)
¥Introduced as a mid-1962 change for manual transmissions was the red filler hole plug gasket with the "Trans. Fill Only" message.

1963 Transmissions
Code Application Part # Case # Gear ratio, notes, etc.
S 3 Speed MT
In light of the mid-'62 change described above, the 1963 AM may be incorrect in showing 3826177 continued from previous year. P&A-10/63 identifies the case as 3826176.
[3826177-?] 38261763.50, 1.99, 1.00 rev-3.97
R 4 Speed MT
See table below for detailed descriptions of 4 speed transmissions
 3799363* 3799364 3799363 continued from previous year (1963 AM; P&A-34 10/62)
BPowerglide
As explained for 1961, powerglide transmissions were delivered to the assembly line under a complete transaxle assembly
3745640 = transaxle assembly (1963 AM) 3788375 = transmission;

1964-65 Transmissions

 

Code Application Part # Case # Gear ratio, notes, etc.
S 3 Speed MT
3840785 3849447 (1964 AM; P&A-34 10/63)
R 4 Speed MT
Major design changes were implements in 1964 and carried forward for 1965. See table below for detailed descriptions of 4 speed transmissions.
  3837288*
early '64
3833192* 3837288 was the "First design ", a modification of #3833191*, the '64 car 4 speed that used a larger diameter 14 spline input shaft. (1964 AM)
3864460*
late '64 - '65
3833192* 3864460 was the "Second design" (1965 AM; P&A-34 10/65)
BPowerglide
As explained for 1961, powerglide transmissions were delivered to the assembly line under a complete transaxle assembly
1964 3838478 = (transaxle assembly (1964 AM) 3857347 = transmission (P&A-34 10/65)
1965 3857445 = transaxle assembly (1965 AM) 3866774 = transmissio; (P&A-34 10/65)


4 Speed Transmission Component Summary1
component Early '612 Late '61 - Early'623 Late '62 - '63 Early '64 Late '64 - '65
Transmission part # 3785452 3788154 3799363 3837288 3864460
Case # 3782978 3788155 3799364 3833192
Backup light boss drilled and threaded but plugged4 undrilled
Lube drain hole present absent
Lube filler hole dia. 1/2" 7/8"
gear ratio 1st-4.26   2nd-2.35  3rd-1.48   4th-1.00 rev-4.27 1st-3.65, 2nd-2.35, 3rd-1.44, 4th-1.00, rev-3.658
Input shaft 3785456
12 splines
3840297
14 splines
Main shaft 3785453 3813663 3852240
Main shaft bearing 907259 907443
Countershaft 3775061 (teeth: 30,27,21,14,15)
Countershaft gear 3784644 6257855 3851512
Clutch gear & synchronizer assy 3785455
(30o bevel angle)
3814014
(30o bevel angle)
3840294
(30o bevel angle)
3851508
(45o bevel angle)
1st gear (31 teeth) 3775090 38522445
2nd gear 3775093
26 teeth
6257856
28 teeth
38373005
28 teeth
2nd gear thrst brg 9415297 -- --
1st/2nd synch assy 3780688 38139015
1st/2nd blocking ring 3779482 3813902
3rd gear (22 teeth) 3780252 3821380 3837298
3rd/4th synch assy 3779484
3813904
3794203
3rd/4th blocking ring 3779485 3813905 3849964
reverse idler 3780111 3833198
reverse inhibitor assy 3775070 ? ?
Notes
1 - Data was drawn from Assembly Manuals, P&A catalogs (cautiously) Engineering drawings and documents, and other GM documents, as well as Craig Nicol's article on 4-Speed transmissions in the Oct 2003 CORSA Communique, and his separate table of 4 speed transmissions. This reexamination yielded some differences from Nicol's in the inclusion of 3788154 as the FC 4-speed in '61 - '62, and in part numbers in a few places.
2- The Engineering drawings also include two other assemblies with the 4.26 ratio first gear. 3772149* is the earliest drawing of which other assemblies were modifications, including 3785452 and 3772157*, the latter appears to be an early prototype FC 4 speed with a 28-tooth 2nd gear. Only 3785452 was put into production.
3- The rationale for 3788154 is described above in the 1961 transmissions section.
4- The boss for the unused backup light switch is drilled and plugged, usually, although some people report it is undrilled.
5- In the 1993 Vol 21(#2) issue of CorvanAntics, Bob Helt reported that all of the '64 - '65 4-speed FC transmissions that he had inspected were "hybrids" with late style 3rd and 4th (clutch) gears but with the earlier ('61-'63) 1st and 2nd gear components. Why so was a "mystery".



Differentials (Rear axles)
Where to find the ID codes - click images to enlarge

Case numbers are on the upper bellhousing cover flange differential case # location

For '61 -'64 differentials, ID codes are on flat retangular boss on lower feft side.transmission code

For '65 differentials, ID codes are lightly engraved on right side of case .transmission code



Example late codetransmission code


Example early codetransmission code

In 1964 the lube drain hole (green circle) was eliminated. The red circle is the transmission drain hole. transmission code

Parts and Accessory catalogs, section 5.505, generally give part numbers for differential cases not the complete differential assemblies. Assembly Manuals give the numbers for either the complete differential (for manual transmssions) or for differential+transmission assemblies (for powerglides). Data here is supplemented with information from other sources, including engineering drawings and documents and other GM documents

1961 Differentials
CodeApplicationCarrier Differential assembly (DA) and/or Transaxle assembly (TA)
BQ3.27 with MT 3780270 3779576 DA (P&A 616-1 12/60)
BC3.27 with PG 3780272* 3783257 TA (P&A 616-1 12/60)
The differential with a 3.27 gear ratio was available only for a while in the beginning of the 1961 model year.
BL3.89 with MT 3780270 3783095 DA (1961 AM)
BY3.89 with PG 3780272*  3795640 TA (1961 AM)
 

1962 Differentials - All 3.89:1 ratio
CodeApplicationCarrier Differential assembly (DA) and/or Transaxle assembly (TA)
HEMT 3826196*
(P&A 34 10/62)
E - 3783095 - DA ('62 AM)
L- 3826217 - DA ('62 AM)
HFPG 3780272*
(P&A 34 10/62)
3780272 - TA (P&A 621A 10/61)
HL Posi with MT 3826196*  3826221 - DA (1962 AM)
HM Posi with PG 3780272*  3826211 - TA (1962 AM)
A mid-1962 model year change was increasing the diameter of the differential filler hole from 1/2" to 3/4" pipe thread. This was done at the same time that the filler hole of the 3-speed MT was elevated an inch and increased to a 7/8" diameter. (1962 AM, Central Office Advanced Information Notice A.I. 62-13; 3/12/62)

1963 Differentials - All 3.89:1 ratio
ID tag
At least for '63 and '64, differential assemblies were identified with a small metal tab of a specific shape artached under a bolt of the differential cover. Most of these probably are long gone. 1963 coding was as follows:
Tag 3741069 - 3.89 axles (HE, HF, HL, HM); Tag 3756491 - 3.55 axles (HB, HJ, HJ and HK)
Tag 3741070 - 3.08 axles (HN, HP); no tag - 3.27 axles (HA, HC, HG, HH) (Axle ID Chart 3826800*)

CodeApplicationCarrier Differential assembly (DA) and/or Transaxle assembly (TA)
HEMT
3826196* (P&A 34 10/62)
3826217 = DA ('63 AM; AIDC)
HFPG Early - 3794252* 3795640 = TA ('63 AM)
Late - 3826197* (P&A 34 10/63) 3794236 = DA (AIDC) 3794246 = TA (AIDC)
HL Posi with MT 3826196* (P&A 34 10/62) 3826221 = DA ('63 AM; AIDC )
HM Posi with PG 3826197* (P&A 34 10/63) 3794248 = DA (AIDC) 3794240 = TA ('63 AM; AIDC)

Information sources: '63 Assembly Manual (AM), Parts and Accessory (P&A) catalogs, and engineering Axle ID Chart (AIDC)#3826800.


1964 Differentials - All 3.55:1 ratio; carrier with mounting pad for car leaf spring
CodeApplicationCarrier Differential assembly (DA) and/or Transaxle assembly (TA)
HQ MT Early -3848104* (P&A 34 10/63),
Late - 3856267* (P&A 34 10/65 )
L-3856262= DA ('64 AM; F&P)  
HS PG 3848105* (P&A 34 10/63), ID tag 3741070   3838479= DA (F&P); 3838478 = TA ('64 AM; F&P)
HR Posi with MT ? 3856265 = DA ('64 AM; F&P)  
HT Posi with PG ? 3838482 = DA (DIDC; F&P) tag 3741070
3838481 = TA ('64 AM; F&P)

Information sources: GM Facilities & Production Planning Department document dated 3-17-1964 (F&P); '64 Assembly manual (AM); Parts and Accessory (P&A) catalogs; engineering Differential ID Chart (DIDC) #3849014. ID tag numbers come from Differential Carrier Assembly chart #3849014



1965 Differentials - All 3.55:1 ratio
CodeApplicationCarrier Differential assembly (DA)and/or Transaxle assembly (TA)
AV MT 3857450* 3857446 = DA (1965 AM; DCAC2)
AX PG 3857451* 3857447 = DA (DCAC3); 3857445 =TA (1965 AM)
AW Posi with MT 3857450* 3864308 = DA ('65 AM)  
AY Posi with PG 3857451* 3864310* = DA (DCAC3)  

Is 3864309 a PG or MT differential? The '65 AM says PG, the engineering document for the unit says MT; I have favored the engineering document, and substituted the corresponding PG unit 3864310. Reference also Differential Carrier Assembly Charts 3868792* (DCAC2) and 38687933* (DCAC3).


Distributors & Vacuum Advances
Where to find the ID codes - click on image to enlarge

Distributor part number is stamped on the body of the unitvdistributor code

Vacuum advance code (usually the last three digits of the part number) is stamped on the advance arm.vdistributor code


1961 Distributors
Part # ApplicationVacuum Advance
1110258Manual Transmission 1116152
1110259Powerglide 1116177
1962 Distributors
Part # ApplicationVacuum Advance
1110269Manual Transmission 1116198 (217)
1110271Powerglide 1116200 (951)

1963 Distributors
Part # ApplicationVacuum Advance
1110294 80HP Manual Transmission 1116199 (217)
111029580HP Powerglide 1116200
1110296102 HP All 1116199

1964 & '65 Distributors
Part # ApplicationVacuum Advance
1110310 95 HP Manual Transmission 1116229
1110311 95 HP Powerglide 1116230
1110319 110 HP All 1116230

Carburetors
Where to find the ID codes - click on image to enlarge

Carburetor part number and date code are stamped on metal tag.carburetor tag

Month of date codes is abbreviated as a letter, where:
A = Jan, B = Feb, C = Mar,
D = Apr, E = May, F = Jun,
G = Jul, H = Aug, J = Sep,
K = Oct, L = Nov, M = Dec
Year in code is:
1 = 1961, 2 = 1962, 3 = 1963,
4 = 1964, 5 = 1965
Modification sequence in code is:
A = 1st, B = 2nd, C = 3rd, etc.


1961 Carburetors
Part # ApplicationJetFloat SettingFloat Drop
7019100 PG (early) .048 1-7/32 1 3/4
7019101 MT (early) .049 1-7/32 1 3/4
7019110 PG (late) .050 1-7/32 1 3/4
7019111 MT(late) .050 1-7/32 1 3/4
In Canada, 7019111 was used for both MT and PG.

1962 Carburetors
Part # ApplicationJetFloat SettingFloat Drop
7020100 PG .049 1-7/32 1 3/4
7020101 MT .050 1-7/32 1 3/4

1963 Carburetors
Part # ApplicationJetFloat SettingFloat Drop
7023100 80HP PG .049 1-3/16 1 3/4
7023101 80HP MT .050 1-3/16 1 3/4
7023102 102HP (PG & MT) .050 1-3/16 1 3/4

1964 Carburetors
Part #ApplicationJetFloat SettingFloat Drop
7024025 95HP MT (PG & MT) .053 1-1/16 1 13/16
7024024 110HP (PG & MT) .050 1-3/16 1 3/4
 

1965 Carburetors
Part #ApplicationJetFloat SettingFloat Drop
7025025 All PG & MT .053 1-1/16 1 13/16
Although the '65 Assembly manual gives 7024025 as the carburetor for 1965, the P&A catalogs are in close agreement with Bob Helt's book, that 7025025 was the only carburetor used this year.



Cylinder Head Part #s
This list is much indebted to Bob Helt's Cylinder head article in the 1993 CORSA Communique 15(9).
Where to find the ID codes

Cylinder head part numbers are located on the side of the headtransmission code


1961 Cylinder Heads
Cylinder heads lack automatic choke thermostat; have holes for 6 valve cover clamps
Part # Cast # Engine Compr RatioNotes
3786583* 3786589* 80 HP 8.0 145 CI
3786584* 3786588* 80 HP 8.0 145 CI

1962 Cylinder Heads
Cylinder heads have automatic choke and holes for 4 valve cover clamps
Part #Cast #EngineCompr RatioNotes
3817566* 3817568* 80 HP 8.0  
3786585* 3786590* 80 HP ? 145 CI, also Low compression export - 6 clamps
3786586* 3786591* 80 HP ? 145 CI, also Low compression export comb chamber
3786957* 3786590* 80 HP ? 145 CI, also Low compression export comb chamber

1963 Cylinder Heads
Part #Cast #EngineCompr RatioNotes
3817566* 3817568* 80 HP 8.0 145 CI
3817567* 3817569* 80 HP ? 145 CI, also low compression export
3813511* 3813516* COPO 102 HP 8.77 (actual) 145 CI

1964 Cylinder Heads
Part #Cast #EngineCompr Ratio Notes Bob Kirkman only identifies the 1st design heads. However, P&A 34, Oct 1965, includes both 1st and 2nd design heads for '64, as shown here.
3839886* 3839887* 95 HP ? 95 HP "1st design" 164 CI  
3819875* 3819876* 110 HP 9.0 110 HP "1st design" 164 CI
3856625 3856626* 95 HP ? 95 HP "2nd design" 164 CI
3856631* 3856632* 110 HP 9.0 110 HP "2nd design" 164 CI

1965 Cylinder Heads
Part #Cast #EngineCompr RatioNotes
3856757 3856743 95 HP 8.3 164 CI
3856758 3856759 110 HP 9.3 164CI


Generators and Regulators
(Alternators in '65)
Where to find the ID codes - click on image to enlarge

Generator part number and date code are stamped on the red Delco-Remy tag.generator tag

Regulator part number is stamped on mounting bracket.regulator code

Alternator part number and date code are stamped on the alternator housing.generator tag

In the date code, the Year is:
1 = 1961, 2 = 1962, 3 = 1963,
4 = 1964, 5 = 1965
followed by the month, which is abbreviated as a letter:
A = Jan, B = Feb, C = Mar,
D = Apr, E = May, F = Jun,
G = Jul, H = Aug, J = Sep,
K = Oct, L = Nov, M = Dec

which is followed by the day.


1961-63 Generators & Regulators
Generator Part # Amps stock/option Regulator
1102227 30A stock 1119001
1105135 35A L.C.I. FAO 650 / RPO K71 '61: 1119635*
'62-'63: 1119604

The 35 Amp LCI generator was intended for FCs that had a high current demand, such as ambulances, emergency vans and other service vehicles. LCI stands for "Low Cut-In". Generator cut-in is often defined as the speed at which the generator produces a voltage equal to that of the fully charged battery. The specifications show that the 5135 unit could produce 14 Volts (and 35 Amp) at 1730 RPM, versus 2230 RPM (and 30 Amp) for the stock generator. In order to produce higher current at lower RPM, a larger generator with more armature windings is needed, and this is well reflected in the substantial weight of the 5135.


1964 Generators & Regulators
Generator Part # Amps stock/option Regulator
1102336 35A stock 1119305*
1105135 35A L.C.I. RPO K71 1119604

1965 Alternators & Regulators
Generator Part # Amps stock/option Regulator
1100639 37A stock 1119515*
1100698 47A RPO K84 1119519