fivebolt bellhousing identification

[Dan Case]

Case Materials: Main Case and Tail Shaft Housing
The mystery time frame for production Cobra case materials was roughly between when “iron cases” for CSX2115 (completed as a car June 1963) and “aluminum cases” CSX2136-2138 (completed as SAI team race cars about August 1963). CSX2126 would NOT be in the discussion because it was finished before CSX2080 (It was a running car about the beginning of February 1963.).

Gears
The type of gear set installed in new transmissions was not permanently marked on them. Production iron cased units in standard Fords came from Borg-Warner with small metal tags affixed by a tail shaft housing bolt. The information on the metal tags identifies the assembly. I have been told that the aluminum cased transmissions sent to Shelby’s works were only marked with temporary paper tags to identify the individual transmission assemblies, i.e. engineering version or gear set.
I don’t know if the iron cased models in the earliest Cobras used were tagged or not, never seen one in person nor a detailed set of factory pictures. The very earliest Cobras were loaded with parts, especially in the engine bay, that most Cobras were never to use again. AC Cars considered CSX2001 the first production car and the first shipments of chassis to America to both coasts were of chassis very much like CSX2001. Once past the chassis line at AC cars there was a divergence of final assembly details because multiple shops finished the cars to the same concept but with different hardware. While not an exhausting accounting: Dean Moon’s shop and employees were used until Shelby took over an existing race car shop including CSX2000 in its first ‘American’ outfitting, various Carroll Shelby owned companies, Ford Motor Company to which it is believed chassis CSX2008 was sent, AC Cars Ltd including CSX2025, CS 2030, CS 2130, CS 2131, CSX2142, and CSX2186, Ed Hugus' company European Cars of Pittsburg PA many early cars in 1962 into early 1963 including the first production car CSX2001, RRR Motors of Homewood IL completed CSX2082 maybe, and Holman-Moody obtained CSX2009 to finish and use as a race car.

? sets = standard Ford of some type probably with cast iron cases. We do not know if the prototype Cobra received a prototype or preproduction transmission assembly in England and or America. Almost anything could have been possible as for example CSX2000 received the first Experimental High Performance 260 (XHP-260-1) prototype racing engine Ford engineers built when it got its second engine after arriving in California from England. CSX2000 was originally tested by AC Cars with a Fairlane 221 2V engine. AC Cars, Ken Rudd, and Ford had been cooperating on Rudd’s ACE RS2.6 cars long before Mr. Shelby showed up at AC Cars. The ACE RS2.6 cars used Ford Zephyr 2.6 liter inline six cylinder engines (RS2.6 = Rudd Speed 2.6 liter engine) and Borg-Warner manual transmissions. We have no idea what version of Borg-Warner transmission was installed in CSX2000 behind its Fairlane 221 engine. Legend says FoMoCo shipped an engine to AC cars for CSX2000. I don’t recall any mention of a transmission being shipped for prototype work. One could speculate that the “original” Cobra transmission was the same model an ACE RS2.6 used. In America CSX2000 and the other very early Cobras except one were fitted with XHP-260 engines got some type of Borg-Warner iron cased manual transmission. CSX2006 was fitted with a Fairlane 260 2V engine, at this time we don’t know the model year of that engine or if it was a prototype or production engine. At this time we have no idea what specific model the transmissions were or even if they were the Ford 23 tooth spline input like a 1962 Ford would have used or the new Ford ten tooth spline design that was coming for the 1963 model year. It was not uncommon for engineering lead times to be fourteen to eighteen months. Said another way, many parts and assemblies that would become standard production ones were first made in prototype or preproduction sample forms as much as eighteen months before the first production car it was planned for was assembled. XHP-260 engine parts were being made by April 1961. Ford was working towards offering a HP260 engine option package for the 1963 model year Falcon, which failed to materialize. Cobras ended up using some of the HP260 engines that were manufactured. It is real easy to imagine transmissions planned for production release in the summer of 1962 for 1963 model year Fords being available in preproduction form by the time CSX2000 was flown to California in February 1962, perhaps even as early as mid 1961 when AC Cars was developing CSX2000.

B sets = standard Ford style iron cased Galaxie transmissions and believed to have been used in early Cobras in the CSX20xx range (we don’t know exactly when the XHP-260 was replaced with the HP260) through early CSX21xx cars used cast iron case transmissions. Cars covered by that range were powered with HP260 and early 1963 model year, think December 1962 through maybe all of February 1963, HP289s.

From the 1962 (dated 11/30/62) Cobra FIA registration there was a standard and alternative gear set listed. The standard was the Ford B set from 1962.
Standard Alternative (alternate transmission part number XCO-270)
2.36 2.20
1.78 1.48
1.41 1.18
1.00 1.00

From the 1963 (dated 09/20/63) Cobra FIA registration the only the B gear set is listed:
2.36
1.78
1.41
1.00

From the 1964 (dated 02/06/64 Cobra FIA registration):
Standard Alternate w/2.20 1st Alternate w/2.33 1st
2.36 2.20 2.33
1.75 1.63 1.61
1.40 1.31 1.20
1.00 1.00 (no number listed)

[Dan Case]

A very early, see time frame above, HP289 engine prepared for installation into a new Cobra chassis is shown in a factory photo with an iron cased transmission attached. The very large engineering number stenciled, the picture is in black and white but Borg-Warner used bright yellow paint for the number stenciling, on the right side of the transmission case reads C3AA H. The C3AA-H transmission is one model used during part of the 1963 model year for 427 c.i.d. powered Ford Galaxies. At least some 1963 model year 427 Galaxie transmission models had oiling grooves cut vertically into the faces of gears. This detail was unique to 1963 427 Galaxie transmission. It is not known if the C3AA-H model used grooved gears or not. To add to the confusion between the Ford listings and the findings of the 427 Galaxie owners group five (5) different transmission assemblies as possible for 427 powered Galaxies in the 1963 model year: C3AA-H, C3AR-J, C3AR-K, C4AR-N , and C4AR-S. I presume all these versions used Ford ten tooth spline inputs. At this time I have no idea what the engineering specifics are for all these versions.
A related subject is clutch and pressure plates.
23 Spline Disc Springs Pressure Plate Diameter
1962 221 heavy duty C20Z-7550-A 6L-6S C20Z-7563-B 10½”
1962/64 221/260 C20Z-7550-C 6L-6S C20Z-7563-D 10”
1962 260 heavy duty C0AA-7550-A 8 C20Z-7563-B 10½”
1962 260 B8A 7550-C 8 C20Z-7563-D 10”
So what clutch system did AC Cars used with the 221 2V engine and what did Dean Moon’s shop used when engine XHP-260-1 was installed in CSX2000 in California. We have no idea, either could have been one of the above or a prototype and or preproduction of what would become the 1963 model year HP289 assembly or even some type aftermarket set.


Cobra wise, all other Ford and General Motors (GM) (K set) cars excluded:
B set = standard passenger car gears, also used in Cobras 1962-63.

XCO-270 transmission set, origin unknown at this time.
J set = standard passenger car gears metallurgically, may or may not have gotten into new Cobras.

K (high nickel) set = installed into aluminum cased Cobra transmissions, street and race, introduced sometime in the CSX22xx range it is believed, example CSX2246 had a K set originally, my black car CSX2310 was fitted with a K set. (The K gear ratios originated in some high performance GM cars.) Listed as the alternate gear set in the February 1964 Cobra reconfirmation of registration for roadsters and coupes with the Fédération Internationale de l'Automobile (FIA) race sanctioning organization.
L (high nickel) set = installed into aluminum cased Cobra transmissions, street and race. Listed as the standard gear set in the February 1964 Cobra reconfirmation of registration for roadsters and coupes with the Fédération Internationale de l'Automobile (FIA) race sanctioning organization.

M (high nickel) set = introduced into aluminum cased Cobra transmissions, race and maybe street, introduced sometime in the CSX23xx range it is believed, it is believed that the later the chassis was the more likely it was fitted with a M set. Legends says they were called “Sebring” gears because SAI first used them in their race cars at the 1964 Sebring race. The Feb. 6, 1964 reconfirmation of what was submitted to the FIA (with pictures of CSX2138 and the first Daytona Coupe included) shows L gear ratios standard and K ratios as an alternative. The M ratios are not listed at all on that document. SAI was into finishing late CSX22xx and early CSX23xx chassis at the time. My black car (CSX2310, end of March 1964) came with a K set.

The tough part to deal with is that chassis were not finished in order so it is meaningless to think that since car CSX2xxx was fitted with "such and such" that chassis CSX2xxx±1 or 2 or x received the same part or assembly. Early made parts and or assemblies can be in most any car but late made parts or assemblies cannot.

Physical Information
The original transmissions fitted to Cobras, all confirmed models, had an overall assembled case length of 27 3/8 inches including the 1/2 inch spacer between the cases. This case configuration is the same as was used in the 1962-64 Galaxie or big Mercury and the 1963 Fairlane T10's. Cobra required and used the early narrow bolt pattern case design because all manual transmission equipped cars fitted with 5 bolt bell housing engines. The casting numbers on the narrow pattern T10 main cases are T10 B-1 (iron) and T10 L-1 (aluminum).
(Note: 1965-66 six bolt bell housing engine Ford version of T10 main case will fit a 1962-64 five bolt engine bell housing because it has both the early and late sets of mounting holes. There is a problem however as the transmission front bearing retainer will need to be changed because the five and six bolt bell housings each use bearing retainers with different outside diameters where they fit into the index hole in the center of the back of the bell housing. The five bolt bell housing has a smaller diameter index hole than the six bolt bell housing, so a five bolt bearing retainer will not fit snugly into a six bolt bell housing and the six bolt retainer will not fit into a five bolt bell housing because it is too big. One has to be aware of this because the transmission front bearing retainer fitting snugly into the hole in the back of the bell housing indexes the transmission main shaft centerline to the engine crankshaft centerline and a loose fit won't index the centerlines properly. While the transmission is out, it is a good time to check the bell housing runout to ensure the centerline of the hole in the back of the bell housing lines up with the crankshaft centerline as the maximum per Ford specs is 0.015 inch and some aftermarket scattershields have been found to be off as much as 0.125 inch, which is 1/8 inch! Bell housing misalignment can result in premature pilot or front bearing failure or a catastrophic clutch failure.)
The correct Cobra and Galaxie tail housing measures 17 3/8 inches front to rear and the tail housing casting numbers are T10 B-7 (iron) and T10 L-7 (aluminum). The shifter mounts to the Cobra tail housing with 3 bolts in an "L" pattern that has the vertical part of the "L" toward the front of the tail housing and the center of the top front bolt hole for the shifter mount is 4 1/4 inches from the front of the tail housing. The shifter assembly is a 1962-64 Galaxie / Fairlane T10 unit with a short, straight Cobra unique ever.
(Note: Contrary to mythology the short style Sunbeam Tiger shift lever is not the same as a Cobra’s. The Cobra and Tiger lever assemblies use different mounting fasteners and ancillaries. The Cobra lever assembly has no provision for rubber isolation mounts while the Tiger model does.)
The Mustang, Falcon or Comet T10 tail housings are 3 inches shorter than a Cobra unit and the shifter is not in the right location, so neither the tail housings or shifters will properly fit a Cobra. The 1964 Fairlane T10 tail housing has the correct shifter location, but it is about 1 1/2 inches shorter, so to use it in a Cobra will require a longer driveshaft.
The 63-64 Galaxie or 63 Fairlane T10's fit a Cobra and the ones from the 406, 427 and Hi Po 289 cars are close ratio units as are many from the 390 engine cars. The other Galaxie and Fairlane T10's and virtually all of the Mustang and Falcon ones were originally wide ratio units with the exception of the relatively few units with the "M" ratio gears used in the 1965-66 Shelby GT 350's.
Borg Warner identifies the various T10 gear ratio sets with a letter designation and the first gear set to use that particular combination of ratios has that letter assigned to the cluster gear because often the cluster alone is unique to that particular gear set. For example, T10 B-8 is the part number assigned to the first Ford T10 cluster gear and it denotes the "B" ratio set. The other close ratio Ford cluster gears are T10 J-8, T10 L-8, T10 M-8 and the T10 K-8 used in some Cobras. Often times only one gear on the cluster itself makes it different from the other gear ratio sets as can be seen farther below where the cluster gear tooth counts are shown. The quickest way to tell for sure what gear ratio set is in a particular Ford T10 is to count the teeth on the middle two gears on the cluster to identify which cluster gear it is.
Likewise, the first time any of the other 1st through 4th gears are used, it receives the letter designation of the first cluster gear it is used with and then keeps that designation regardless of the other gear sets it is used with. All of the 1960's Ford design T10 first gears are 36 teeth except the wide ratio Q first, so they will interchange between the various Ford close and wide ratio sets. For example, T10 E-12 is a nickel alloy first gear first used in a GM application and it is also the first gear for the L, M, and K nickel alloy gear sets and it will also fit the non nickel alloy B, J, H and sets.
The close ratio Ford input shafts are all 26 teeth except the GM "K" input used in some Cobras, so they will interchange between all of the Ford close ratio sets except for the K set. Be aware that the input shaft length on the B and L inputs is a bit shorter and they measure 8 1/2 inches in length because they are for use with the 390, 406 and 427 engines. The B and L inputs can be used with a 260 or 289 by using the factory Ford extended pilot bearing used in early Broncos (C5TZ-7600-D) or by adding 3/8 inch to the pilot tip, which extends it to the small block length of 8 7/8 inches.

[Dan Case]

There are Borg Warner part numbers for each gear along with OEM part numbers for any T10 gears used in an OEM application and sometimes there is more than one OEM number if more than one car manufacturer such as GM and Ford used that particular gear. Borg Warner T10 gear numbers are relatively simple to follow as the only change in the gear part number is the letter designation itself, which is replaced with a __ in the example below:

T10__ -8 Cluster gear
T10__ -16 Input shaft (4th gear)
T10__ -11 3rd gear
T10__ -31 2nd gear
T10__ -12 1st gear
Ford T10 Close Ratio Gear Tooth Counts:
B close (1962)* L & J close** M close*** K close (GM)****
1 36 1 36 1 36 1 36 (GM 1358577/Ford C3AZ-7100-F/BW T10E-12)
2 32 2 30 2 29 2 30 (GM 1358579/Ford C3AZ-7102-E/BW T10E-31)
3 29 3 29 3 27 3 29 (GM 1358576/Ford C3AZ-7B340-A/BW T10E-11)
4 26 4 26 4 26 4 27 (GM 9771377/BW T10K-16)
C 29-23-20-17 C 29-23-19-17 C 29-25-20-17 C 28-23-19-17 (GM 9771378/BW T10K-8)

* The B gear set may have been used in early Cobras.
** L gear sets are high nickel alloy, J gear sets are not and the J sets were used in HP289 equipped Fairlanes and 390 Galaxies.
*** The M set is a high nickel alloy and also called the "Sebring" gears and was first available in 1964 for the Sebring race.
**** The K close ratio gear set is a high nickel alloy gear set originally used in GM cars (Pontiacs) from 1957 to 1963 and it was used in some Cobras. A GM clutch disc is used because the GM input shaft diameter is larger. 1st, 2nd & 3rd gears in the K set are the same as used in the L ratio gear set. Also required is a different pilot bushing in the tail of the crankshaft because the GM pilot tip is smaller in diameter than the Ford parts.

“L” T10L-8 (high nickel) = C3AZ-7113-H (cluster)
“L” T10L-16 = C3AZ-7017-G (4th)

“M” T10M-31 = C3AZ-7102-G (2nd)
“M” T10M-11 = C3AZ-7B340-C = S1MS-7B340-A (3rd)
“M” T10M-16 (4th)
“M” T10M-8 = C3AZ-7113-K (cluster)

“J” T10J-16 = C3OZ-7017-F (4th)


The Ford T10 wide ratio gear set tooth counts are provided below for gear identification purposes. The "Q" ratio gear set will not fit a Cobra because it uses its own main shaft with a different diameter on the tip that fits into the rear of the input shaft and a "Q" main shaft is not available in the Cobra length.

H wide ratio Q wide ratio (66 Mustang only)
1 36 1 34
2 30 2 27
3 28 3 24
4 24 4 20
C 31-24-19-17 C 28-21-18-18

T-10 Gear Ratios:
B XCO-270 J & L M K (GM) Mystery
(Cobra race (Cobra race 2nd alternate
alternate 1962) 02/06/64 FIA registration)
1 2.36 2.20 2.36 2.36 2.20 2.33
2 1.78 1.48 1.76 1.62 1.63 1.61
3 1.41 1.18 1.41 1.20 1.31 1.20
4 1.00 1.00 1.00 1.00 1.00 (not listed)
Rev 2.42 2.42 2.42

November 30, 1962 dated FIA registration papers lists an alternate transmission.
XCO-270 alternate

The May 1965 issue of the SHELBY AMERICAN PERFORMANCE EQUIPMENT parts book has limited Cobra specific transmission information listed. The worst aspects of this book’s listing are:
1) almost no prototype, preproduction, SAI race team only, very early Cobra, custom ordered, or limited use parts are listed.
2) does not cover locally sourced parts and materials that shops besides Shelby Venice and Imperial Hwy used during car completions.
3) does not cover all the parts Shelby Imperial Hwy used to finish and or refit the last Cobra roadsters in most of 1965 and 1966
4) many small parts are not listed in any way.
5) some of the parts listed are service parts, i.e. production parts were no longer available so factory authorized replacement parts were listed.
So with the warning above, here is what is listed as SERVICE transmissions May 31, 1965.
C3AZ 7003- H Transmission, 4-Speed Stock Cobra Steel Borg/W Ford Ea 320.90 258.32
S1CS 7004 Transmission, 4-Speed Stock Cobra Aluminum AS2T/O-L Warner Gear Ea 323.13 258.50
S1CR 7005 Transmission, Pontiac Racing Gear 93, SK4516 AV Ford B/W Ea 319.80 223.86
S1CR 7006 Transmission, 4-Speed Aluminum Sebring Type Racing, SK4516 QK Ford B/W Ea 381.35 266.95
C2AZ 7039 C Transmission-Housing For Tail Shaft BWT-10-B7 Strong Competition Warner Gear Ea 36.63 35.64

[peterpjb]

Dan, I really appreciate very much your wealth of knowledge, thanks for all these Informations!

[Dan Case]

Originally Posted by peterpjb

Dan, I really appreciate very much your wealth of knowledge, thanks for all these Informations!

You are welcome.

We have collected a lot of information on Cobras. I started studying parts making them up circa 1971. I started some original car owner's groups years ago; including several original owners. Having fifty plus owners of street and race (including street and race car original owners) Cobras and a few of the world’s most dedicated to authenticity restorers to collect data from all historic and modern points of view has helped me build many files. Doing surveys is fun, “… if you car has one or more original tires on it please go get every tiny bit of information you can find and send it in for collection….” Many of the people in this group own or have owned multiple original Cobras street and race Shelby and privateer, 427 Cobras street and race, AC 289 Sports, and even one friend owned a Daytona Coupe long ago. Just guessing, but this group I can draw help from has or has had maybe 200 or more original cars goes through their garages. Big data base.

Until recently an enormous amount of documentation (originals mostly) on the parts going into new Cobras was in one collection. Fortunately I got copies of much of the more complicated documents before a fire destroyed the whole library the man had.