BKKSW

Hello -

Reading all the charts on line I can't find certain measurements for which 9" rear end goes in a 65 of 66. This source says a 52 of 54 inch.. how can there be two measurements?

This source says 57.25 for 65/66 and shows a 67/73 from a range of 59.25 to 61.25.

There are more like this showing different answers. Which is right?

I have an opportunity for a 68 GT350 9" rear end, but a 28 spline, but I need to be sure what will fit my 66. If two sizes fit, why would I pick one over the other?

Any help would be greatly appreciated.

Thank you.

norcal_ryan1966

I've always heard the rear ends are 57-1/4". Can you measure your current 8"? I would if I was at the apartment. Also, why not just run the 8". They can handle some power. 400hp if you believe the Internet. A lot lighter. Just my opinion. I've got an 8" in my 66 coupe and plan on building the engine to about 350 crank and possibly converting the tranny from the c-4. I don't think I'll have any problems. It all depends on the cars intended use.

BKKSW

Thanks for the response. I want a 9" for the suspension and power levels I'll be running and also they work great with the different types of lockers available.

57.25 is a common backplate to backplalte measurement.. but I've heard and read they can go two more inches under some circumstances.. and it's those circumstances I'm after.

Thank you.

MonsterBilly

i twill aminly depend on the offset of the wheel you want to use. I picked up a 8.8 explorer rear end and cut 2.25 inches shorter to work. it worked great for 8 years till it broke. i just had it rebuilt

BKKSW

That makes a lot of sense. Thanks.

dodgestang

Without getting into details of how measuring is done it can be said with certainty that the 68 9 inch rear is 2 inches wider than a 65/6 9 inch rear the perches are in the same place however and the rear can physically bolt into the car and be used.. Because of the width change any wheels you pick that 'normally' fit a 65/6 will not fit. A lot of wheels will....later model for instance...but then you will need to also run bolt on adapters in the front if you want matching wheels in the front.

With that said....a 9 inch rear REALLY out of a gt350 will carry a premium price because of what it was in and the types of people who are normally looking for it. A 57-59 Ford 9 inch is the same width a 65/6 mustang and bolts right in without issues.

BKKSW

I have a 57-59 ford 9" and it has 3.10 gears and all the right measurements for a 65/66. But looking at the cost of gears and a trac-loc of some type, new bearings, etc.. this GT350 rear end complete would cost less than upgrading the 57-59. With that said.. which way would you go? This GT350 rear end has a trac-loc which is what the 68's came with and 3.70 gears.. which seams to match up..

norcal_ryan1966

Personally I'd use the 56-59 9 inch. Less of a hassle.

dodgestang

Two questions really (and what I would do doesn't really matter since it aint my car )

1. What's your total cost? Is it really cheaper to buy the GT350 once you factor in cost of new wheels (assuming you have wheels now) than it is to rebuild/update the 57 housing/center section?

2. Do you like wheels with lips or without because without investing time to shorten the 68 housing you will need to use modern looking wheels....no big deal either way....just calling out if you have a preference of say....'I want to run a deep dish wheel'......

Here is a side by side....18x9 modern mag 5 late model take off versus 18x9.5 deep dish style......

BKKSW

1. Currently I own a 57 9" in great shape with large rear drugs also in great shape, cost was $500 delivered to my home (love it when someone can do that).. To buy a bearing/seal kit that includes 3:50's (probably what I'll want) and a trac-loc is $510. Maybe $120 to press in out the seals? Not sure, haven't worked with a 9" in 30 years. (geez I sound old, but I'm really not.. promise.. So say $1150

2. The 68 GT350 includes 3:70's I could live with and a trac-loc. Looks to be in excellent shape. It's available for $600. But.. don't these have tapered axles that can't be shortened? So it must stay 59 1/4" I could use this "as is" if I could wrap my mind in a good way around the wheel equation.

3. And then I'd have a 57 9" for sale. One ultimately costs me $1150 and could later be shortened if desired and there are reasons someone might want to do this. The other $600 but leaves me limited on wheels.


Wheels: Right now I'm looking hard at aluminum steel wheel look-a-alikes. They look like old style steel wheels and take beauty rings and center caps.. but they're aluminum so lighter spun weight, any dimensions I want, and all the advantages of a modern wheel.


Alternate thought: If GT350 9" rear ends really do bring a premium, what would the expected price? Maybe I could just flip it and finance part or all of the work on my 57 9".. ?