I'm sure someone can point me to a place I can find answers to the following questions -

When did they started using the 9" in the F-series trucks?
Did the 9" evolve over the years (change internally and externally)?
Did Ford change from the 31-spline to the 28-spline becuase the vehicles were "de-powered"?

When was the 8" first offered in the F-series trucks?
Were both the 9' and the 8" available in the F-series at the same time (same year)?
If the 8" is considered a "weaker" rear-end, why would Ford offer it in their trucks?

Thanks,

OldFords bad attitudes

 

Are you refering to the 8" from way back when, or the more recent 8.8" rear ends?

Jared

 

[updated:LAST EDITED ON 06-Nov-02 AT 09:38 PM (EST)]Duck, everyone, I'm about to trip over my ignorance and put my foot in my mouth.

I probably mis-stated my questions about the "8" inch. They didn't put those in the F100/150s, did they? I've seen them in the Mustang IIs.

I was thinking of a rear-end such as the one under my wife's 1981 F100. Would it be an 8.8 inch or an 8 inch? Was the 9 inch used that year (1981)?

Her truck came with a 302/2bbl/3-speed. I put in a 351W bored .030 over with a T-5. I need to change the gear ratio in the rear-end because the engine is lugging (75mph at 1800rpm in 5th gear).

But, more than that, I would like to learn a lot more about the rear-ends (differentials)used in the F100/150 trucks, from 1954 through 1987. I know very little about the 8 inch OR the 8.8 inch.

I have a coupla complete nine-inch rear-ends in my portable storage unit (1976 8x8x20ft. box truck), but no 8 or 8.8 inchers.

Thanks for any info you can give me,

OldFords bad attitudes

 

An 81 will definatley have a 9", as will any 82.. They didn't start to use the 8.8 until 83.
Evan
86 F250 HD XLT Lariat Explorer 4x4 ex. Extended Cab: 460 with factory 2.25" catless duals to the muffler(still running the stocker aaargh)
/T19(syncroed granny low)/BW 1345/3.55 geared Full Floater 10.25 and Dana 50 TTB/ 265/75R16 Hankook FR04's on 16x8 Whitespokes(street tires... Need mudders)
78 F150, 351M/C6, eventually to be repowered with a 400

 

>I probably mis-stated my questions about the "8" inch. They
>didn't put those in the F100/150s, did they? I've seen them
>in the Mustang IIs.
Most of the medium sized FOMOCO cars back in the 70's used the 8" which is similar looking to the 9". They are both a removeable carrier type and have no rear diff cover.

>I was thinking of a rear-end such as the one under my wife's
>1981 F100. Would it be an 8.8 inch or an 8 inch? Was the 9
>inch used that year (1981)?
If I'm not mistaken, the 8" inch was not offered in trucks. The 9" was used until '83 or '84. Which is about the time the 8.8" rear came along. The major noticeable difference (other than ring gear size) is the access locations. The 9 with a front removeable carrier and the 8.8 with the rear cover.

>Her truck came with a 302/2bbl/3-speed. I put in a 351W
>bored .030 over with a T-5. I need to change the gear ratio
>in the rear-end because the engine is lugging (75mph at
>1800rpm in 5th gear).
I guess the best bet would be to figure out what gear is in there now, probably a 2.75. Figure out the number of turns of the drive shaft per turn of the wheel. If you want mileage try a 3.25, this should put you at 1800 rpm at 60mph (off the top of my head).

>But, more than that, I would like to learn a lot more about
>the rear-ends (differentials)used in the F100/150 trucks,
>from 1954 through 1987. I know very little about the 8 inch
>OR the 8.8 inch.
Well, there is a lot of information out there, but most of the stuff here will be '65 and up that is mainly what people deal here. You are also blessed with a lot of smart people who frequent this site. Hopefully you'll find out what you wanted.

>I have a coupla complete nine-inch rear-ends in my portable
>storage unit (1976 8x8x20ft. box truck), but no 8 or 8.8
>inchers.
That brings me to a question. Why is that you think your wife's truck has an 8" rear? Is it because it looks smaller or because of the carrier/differential design?

Hope you get what you need.

-Kerry

 

The 8" is a smaller, cheaper, and weaker than a 9", with less parts availability. For the 9", you can get anything you dream of, including a custom built front axle, but they are getting EXPENSIVE. Both the 8" and 9" axles are retained by the bearings, meaning there is very little chance of loosing a wheel/axle assembly, and they also use a dropout carrier. The 8.8" is a whole other animal. It looks more like a D44 than anything else. It is an integrated carrier, with a cover on the rear. The axles are held in by c-clips, that, while more reliable than a Chebbie's, do nothing for me. It is fairly strong, there is a guy locally here who drags late-maodel Mustangs in the 9-second range, and he runs 8.8's. Hope all this helps.

Jared

 

Thanks for the info, everyone. It helps a lot.

I have a 1969 rear-end (complete) that I can take the punkin out of to put in my wife's F100.

Kerry, I just thought the design was different, that's all. For some reason, it didn't look the same as my '69 F100.

Again, thanks everybody.

OldFords bad attitudes

 

[updated:LAST EDITED ON 07-Nov-02 AT 07:43 PM (EST)]http://www.drivetrain.com/ has plenty of info on axles, including lists of which vehicles what years & what changes.
http://www.wilsons4x4.com/axlespottersguide.htm Axle ID
http://www.visteon.com/technology/automotive/solidindependent_axle_spec.shtml OE specs

 

>Kerry, I just thought the design was different, that's all.
>For some reason, it didn't look the same as my '69 F100.

Although the ring gears are the same size (9"), and most of the parts are interchangeable (axles and associated hardware, bearing sizes are the things I can think of to check), some 9" rears do look slightly different depending on the year, casting, and carrier type.

Hope you get the wife's '81 fixed up.

-Kerry

 

http://www.kevinstang.com/Ninecase.htm Pretty good article.

 

First F100 with a nine inch was 1957

'fenders