I'm working on a '68 GT350, 4-spd. cars' rear-end and the question arises as to whether in fact: did "all" GT350's receive 9-inch axles? Or, is it as apparently as is with the "J_Code" cars (what I might suggest these Shelby's started as) some came with 8-inch rears (perhaps automatic transmission (and non "GT"?) examples with 3.00:1 & higher ratios)? ???
And then if so, next, were they "all" equipped with the "C4AW-4025-B", aka. non-"N", "N-case with the "Daytona pinion support and "1330" yoke? ???
The tag reads:
(first line) "DSO - C8ZX-G"
(second line) "3 00 8AD 968"
I got the 3.00 ratio "open" part; perhaps even the "DSO" Dealer Special Order; the "C8ZX" seems reasonable for the '68 vehicle; coupled with the "-G" identifying the unique specification/application; but . . . . . . .? :-\
Scott.
Yes all 68 GT350's were equipped with 9" rearends. They should not be confused with Mustangs which, depending on the options could come with 8" or 9". If the GT package was chosen they received the 9". Didn't have anything to do, for the Mustang, what the gear ratio was. If you check Marti reports and build sheets the coding identifies that the 68 GT350's were ordered/specified as GT cars.
Quote from: J_Speegle on June 05, 2026, 07:35:49 PMYes all 68 GT350's were equipped with 9" rearends.
Thank you for your response! ;D
And "all" being 31-spline "N-case" assemblies also? ???
Scott.
Shelby axle codes are different from Mustang axle codes, just like Mr Speegle mentioned
C8ZX G would not be original to a 68 350. KR auto/AC open
Quote from: TLea on June 06, 2026, 07:48:12 PMKR auto/AC open
Thank you.
That's kinda what I was thinking, but just had to ask. :)
So for clarification, I'm of the belief that a '68 GT350 would have (probably) originally been equipped with a 28-spline, 9-inch axle, utilizing the "C7AW-E" ("single-rib") case and hence the standard pinion support with the "long" 1310 U-joint yoke? :-\
Scott.
Wut?
No.
a 1968 Shelby GT350...
Was a 31 spline, 9 inch with a nodular case, no single rib cases
The id tag you have is from a big block with AC car
https://www.thecoralsnake.com/SUSPENSION.html
All the Shelby axles are listed there
Quote from: Coralsnake on June 07, 2026, 01:53:44 PMa 1968 Shelby GT350...
Was a 31 spline, 9 inch with a nodular case,
The id tag you have is from a big block with AC car
Perfect! ;D
Thank you,
Scott.
GT350 302 4V 31 Spline 9 inch ??? Was a J code 302 4V Mustang a 31 Spline 9" inch?
Quote from: warwick on June 07, 2026, 03:58:53 PMGT350 302 4V 31 Spline 9 inch ??? Was a J code 302 4V Mustang a 31 Spline 9" inch?
Yes.9 inch, 31 spline, Daytona yoke.
Quote from: shelbydoug on June 07, 2026, 05:11:05 PMQuote from: warwick on June 07, 2026, 03:58:53 PMWas a J code 302 4V Mustang a 31 Spline 9" inch?
Yes.9 inch, 31 spline, Daytona yoke.
Any and all "J-Code" examples, are you sure? :-\
Scott.
Previously owned J Code 68 Metuchen built 4 spd NON GT had a 3.00 8" rear axle with a data plate code "5".
Subject has been on other forums, thought the conclusion was GT J Codes came with 3.25 9" while NON GT came with 3:00 8".
Our '68 J Code GT was a 9 inch 28 spline 3.25 limited slip.
Quote from: pbf777 on June 07, 2026, 05:18:39 PMQuote from: shelbydoug on June 07, 2026, 05:11:05 PMQuote from: warwick on June 07, 2026, 03:58:53 PMWas a J code 302 4V Mustang a 31 Spline 9" inch?
Yes.9 inch, 31 spline, Daytona yoke.
Any and all "J-Code" examples, are you sure? :-\
Scott.
I have not seen "Every '68 GT350". That is standard equipment of the GT Package in 1968 as we know it.
The variation from that is the car that should be questioned as far as legitimacy because IT would be out of line.
At this point, there have been so many Shelby cars that have been brought back from the dead by less knowledgeable people with junk yard parts, it would be disappointing to find an inaccurate restoration, but not necessarily surprising.
I can see Ford utilizing 28 spline 9" axles for GT350's auto and 4 spd - and I would expect Mustang J codes with 28 spline 4 spd 9" and GTs autos maybe but autos non GT using 8".
Didn't all 31 spline traction Lok rears have 4 pinion diffs and 28 spline used 2 pinion diffs? And Daytona pinion support came w/31 spline rear.
Ford was too cheap... whoops frugal/efficient to overbuild and they ruled Shelby in 68.
302 4V was a high volume build.
Quote from: warwick on June 08, 2026, 06:48:48 PMI would expect Mustang J codes with 28 spline 4 spd 9" and GTs autos maybe, but autos non GT using 8".
Agreed. As I understand it, "non-GT's, w/ auto, & 3.00 and higher gears", got the 8-inch. :)
QuoteDidn't all 31 spline traction Lok rears have 4 pinion diffs and 28 spline used 2 pinion diffs?
Not sure of the breakpoints in usage, but I've witnessed "2" & "4" pinion examples in either spline count.
QuoteAnd Daytona pinion support came w/31 spline rear.
The "Daytona" type was targeted toward applications which also incorporated the "N-case", and which also generally involved "31-spline" axles; but just note that 31-spline axles didn't necessarily mean you automatically got the others! Just "never say never" with Ford. ::)
QuoteFord was too cheap... whoops frugal/efficient to overbuild and they ruled Shelby in 68.
And this was the frame of mind that started my inquiry! And when you think about it, did a "J-Code" engine option in a little Mustang really need the "Big-Dog" 9-inch? :o
Scott.
QuoteI can see Ford utilizing 28 spline 9" axles for GT350's auto and 4 spd - and I would expect Mustang J codes with 28 spline 4 spd 9" and GTs autos maybe but autos non GT using 8".
Didn't all 31 spline traction Lok rears have 4 pinion diffs and 28 spline used 2 pinion diffs? And Daytona pinion support came w/31 spline rear.
Ford was too cheap... whoops frugal/efficient to overbuild and they ruled Shelby in 68.
302 4V was a high volume build.
Its not really a debate what they used.
Its quite clear based on the build sheets and tag codes.
1968 GT350s were 31 spline cars. Period.
I must admit to sometimes getting confused with the 68 GT350-it all started with back in the day reading the I think it was Road and Track review of the 68 Gt350-it was a white one and had was it called I think "High Performance " package to soup it up and they compared it to a Z/28.........never heard or saw a 302 4V with a "High Performance" Package. Sounded great though.
Now you tell me the little 4 barrel 302 (not TP not Boss) had the same rear as a CJ/427/429....and Ford ate the cost, not only the parts but the assembly.. remember Daytona pinion supports had spacers (ie: shims) vs a crush sleeve.
Hmmmmm. Did the GT350 come with a C servo hipo C4 automatic?? How many tag codes and build sheets you got?
This is one time Ford really acted out of line.
About 250 build sheets and probably 500 warranty tags. Shelby made the modifications to differentiate the cars from Mustang. Its why they also had the 3.89 gears
Cars magazine featured the GT350 that was a custom build with 302 "high output".
https://www.thecoralsnake.com/Curiousity.html
I ask this question out of ignorance: was the Paxton supercharger a factory production option in 68 for the GT350?
3:89 's with a 302 4V sounds painful.
I would think the majority of the buyers wouldn't know the difference between a 28 spline/9" and a 31 spline/9"/daytona pinion support/4 pinion diff - not a great differentiating factor
No Paxtons on 1968 production Shelbys
Quote from: warwick on June 07, 2026, 03:58:53 PMGT350 302 4V 31 Spline 9 inch ??? Was a J code 302 4V Mustang a 31 Spline 9" inch?
Shelby= 31 spline
J code Mustang 28 spline
3.25 and up 9"
3.00 down 8 inch