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28 or 31 Spline Rear

teamlo

Well-known member
Joined
Jan 28, 2006
Messages
259
Agreed. I don't like to make enemies, and I apologize if I offended anyone or insulted his/her intelligence. We're all in this hobby together. I try to learn something new every day. If I've done that, it's a good day.

Terry
 

robert campbell

Well-known member
Joined
Apr 10, 2007
Messages
4,322
Terry,
First I need to apologize for my sarcasm. But, I have been in this hobby since 1972 with my first Mustang when everyone was a Chevy guy in my town. I have grown through the hobby and founded the Kitsap Mustang Club located in Bremerton Washington in the mid 80’s. Watched new owners of the hobby gain knowledge, experience, and love of their cars. Watched a few become snobbish and authoritative in originality of their cars and others they would see. One guy that became truly obnoxious and would nearly attack owners at shows.

I also experienced many abnormalities in the options or basic parts of many Fords, not just Mustangs. Watched original owners be attacked for what people perceived to be wrong parts or options on their cars. I would say, “For Gods sake he or she has owned this car since it was new”, how can you tell them that was not how it was delivered or purchased? I have found actual 1960’s Ford bulletins that has substantiated deviations in basic parts on a car.

From all of this I have learned to expect the unexpected. I will not disagree that the 9-inch rear end was not an option that you can check. But when ordering a locking or posi or equa track or track loc or Detroit locker on the option list, a 9-inch could have been installed in a non-GT optioned car. JBarts car is a non-GT option, J code, 4 speed with trac lock identified on the door data plate list of his Marti report. It lists an option in the option list of the Marti report of a “locking differential”. My bet is it is a 9-inch. Did the order sheet ask for a 9-inch? No. But it came with one because someone ordered a posi rear end. Is it truly and equa lock. Who knows.

I am sorry for my sarcasm and for offending you. I to, learn something new everyday in this hobby. That is why I carefully pass judgement on something that seems “out of the normal”. These cars were assembled by human beings in the 60’s. Anything could have happened. A trac lock in a 6 cylinder car?? Not likely. But I have run into many weird things along my journey in this hobby.

Rob
 

teamlo

Well-known member
Joined
Jan 28, 2006
Messages
259
Thanks Rob. Appreciate the feedback a lot. I've seen a lot of bickering on the site over the years. Usually over silly stuff. Anyway, we all learn things and it makes us better people.

Best regards,

Terry
 

murf104

Well-known member
Joined
Feb 2, 2003
Messages
274
Can anyone produce proof that they have a 68 GT with 3:00 rear axle ratio that has a nine inch differential? 3:25 gears are found with a nine inch - no argument there - this hunt is for a documented GT 68 Mustang with a nine inch factory axle with a 3:00 open gear. Anybody?
 

teamlo

Well-known member
Joined
Jan 28, 2006
Messages
259
It depends on what you consider "proof". In or around 1983, my cousin (who posts frequently on this website) bought a 1968 GT Coupe, J-code with a C4 transmission. Car was out of Metuchen, early build date (Sept. 1967) and was built as a "Local Promotion" for some dealerships in and around the greater Newark, NJ area. So far, I have documented the existance of 3 of these cars, all with the exact same options including exterior color (Sunlit Gold) and interior trim (Black standard buckets). VINs were approximately 50 numbers apart, same build date.

I have the Marti report from the one that he owned (I bought it from him in 1986 and sold it in approximately 1991). Listed on the report is the 3.00 open axle ratio, which is listed on the option sheet of the report as an "optional axle ratio". When he bought the car, it was less engine. He installed a hot small block out of another car he owned at the time. That car also had 4.57 rear end gears (9"), which found their way into the coupe as well (just the center section, not the entire housing). It was a clapped out street racer, but very fast. There is no reason at all in my mind to doubt that the 9" housing in the coupe was the factory rear end housing. The standard rear end gear for the 1968 Mustang with GT equipment group was 3.25 open, presumably to give a little sportier performance for the car, being a GT and all. Hence, the 3.00 was listed as an optional axle ratio.

I can provide said Marti report for 2 of the Sunlit Gold cars as well as a window sticker from the third, all showing the optional axle ratio. I also have the email address of one of the current owners, who posts frequently on the VMF forum. He could certainly confirm the presence of a factory 9" rear end in his car.

Terry
 

murf104

Well-known member
Joined
Feb 2, 2003
Messages
274
Terry, is it your understanding that all GT cars with the 302 in 68 came standard with the 3:25 ratio? IF a person has a GT 68 Mustang with a 3:00 gear it was a special order option? I am new to the 68 Mustang family and ask this only to become educated. Learning the quirks of the 68 cars is like trying to learn a second language and I appreciate everything you guys and gals share with those of us who want to know about "stuff" such as this.
 

teamlo

Well-known member
Joined
Jan 28, 2006
Messages
259
It is my understanding that the GT equipped 1968 Mustangs with J-code 302 4V engine came with 3.25 open as the standard rear axle ratio. I believe that the 3.25 was also standard with the S-code 390 engine. If you had a 428 CJ equipped model, the standard ratio was 3.50, I believe. As far as the X-code 390 2V, that I am not sure about. I think maybe 2.79 or 3.00, as this was intended as more of a "highway cruiser". My area of knowledge is definately not big block cars! Someone else might know more.

So yes, for the J-code GT in 1968, the 3.00 was optional, although I can't imagine they charged extra for it.
 

NosAvrenim

Well-known member
Joined
May 10, 2010
Messages
115
As far as the X-code 390 2V, that I am not sure about. I think maybe 2.79 or 3.00, as this was intended as more of a "highway cruiser".

Based on the X code Mustang registry, the vast majority of X-codes (mine included) came with the 2.75:1 axle ratio ("1" code). The rest came with either the 3.00:1 open or locking axles ("5" and "E" codes).

Since the PO (JohnnyQuest515) put a 4bbl intake on it, I've been considering putting on either 3:25 or 3:50 gears with a TrueTrac differential since there's a little backlash back there. With gas prices continuing to climb, I'm also considering just doing the TrueTrac and keeping the 2.75s since most of my driving tends to be highway and country roads.

~Nate
 

dalorzo_f

Well-known member
Joined
Jan 7, 2006
Messages
1,886
Location
Brisbane Australia
Just a clarification...

The disc brakes were part of the big block package and were added automatically

Not true in '68. Disc brakes were not mandatory with the S code that year. I have a '68 BOSE order Ford line filler with 390 and drums. Drums were a common option for many who were drag racing, less weight and less rolling reisistance.
 

Mosesatm

Well-known member
Joined
Jan 18, 2005
Messages
9,181
Today I looked at a J-code GT/CS. The Marti states that is has the GT equipment and it has the 3.00 equi-loc gears as a "stock" order. Would that be an 8" or 9" rear end?

The Marti is a mile long on this car but going from memory it also has:
Wide ratio 4-speed
PDB
PS
Deluxe interior
Argent wheels with GT caps
8-track
Both consoles
Black-out hood treatment
Black vinyl top
Lime Gold paint (now Aqua)


If Shane or I dont' buy the car the owner is going to list it here.
 

6t8-390gt

Well-known member
Joined
Jul 19, 2004
Messages
490
Location
Central Virginia
Just a clarification...



Not true in '68. Disc brakes were not mandatory with the S code that year. I have a '68 BOSE order Ford line filler with 390 and drums. Drums were a common option for many who were drag racing, less weight and less rolling reisistance.

A 1968 S-code non-GT would come standard with drum brakes...if the S-code was ordered and the GT package also ordered disc brakes became a mandatory additional cost option. This is documented in the original sales brochures and many years of observation.

Additionally, a mid-year update required all S-codes to be GT's. All non-GT S-codes were manufactured early in the model year. I don't know the cut off date...but IIRC the update was publically released around January.

Danny
 
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