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1965 Ford Mustang
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Discussion Starter #1
hello!
i am in the works of swapping out a 200ci for a v8.
a problem i’m currently having is what differential to swap in.

my car is currently a 65 with a 2.83 open diff.

what would be a better differential to handle that extra power from a 302
 

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Are you upgrading to an 8”? I recently upgraded my 8” from an open diff 2.80 to an Eaton Trutrac with motive 3.80 gears. I’m very happy so far. It puts the power down well and is quiet. The 3.80 help many the car fell quicker. I have a 5 speed with overdrive.
 

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a lot of people opt for the 3.55 gears, they are a nice all around gear nice off the line but dont kill you gas mileage. It really depends on what you are looking to do. Is this a cruiser, do you plan to do freeway driving long trips etc, etc. I just went from 2.80 gears to 3.5and they are a lot of fun, Are you putting in an AOD. That may affect your decision as well. If you opt for the 3.55 let me know I have an extra set
 

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what would be a better differential to handle that extra power from a 302
You need what is known as an 8" rear end from a '65 or '66 Mustang. An 8" from a '67 or later is too wide. The most common gear ratios in the '65/'66 were 2.80 and 3.00, neither of which are considered performance ratios. As stated, a 3.40 or 3.55 is a better all-around ratio.
The current rage in the vintage Mustang world is to get a rear end out of a 1996-2001 Explorer which has disc brakes. And a lot of them have 3.55 or 3.73 gears, many with the Traction-Lok limited slip differential. But doing the Explorer swap requires a lot of modification and work to install whereas the 8" swap is a bolt-in swap.
 

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I put a 8" in my 67 that came out of a 70. It has 2.80 gears. Not the best performance wise, but the price was right.

I may go with a 8.8 one day or change teh gears to something better. Undecided at this point.

No matter how much you spend to go faster, somebody has spent more.
 

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1965 Ford Mustang
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Discussion Starter #6
a lot of people opt for the 3.55 gears, they are a nice all around gear nice off the line but dont kill you gas mileage. It really depends on what you are looking to do. Is this a cruiser, do you plan to do freeway driving long trips etc, etc. I just went from 2.80 gears to 3.5and they are a lot of fun, Are you putting in an AOD. That may affect your decision as well. If you opt for the 3.55 let me know I have an extra set
the 3.55 gears sound like what i plan on doing. i just want a cruiser. i rebuilt my c4 to handle a bit more power so i don’t think i’m going to go the aod route.
 

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Discussion Starter #7
You need what is known as an 8" rear end from a '65 or '66 Mustang. An 8" from a '67 or later is too wide. The most common gear ratios in the '65/'66 were 2.80 and 3.00, neither of which are considered performance ratios. As stated, a 3.40 or 3.55 is a better all-around ratio.
The current rage in the vintage Mustang world is to get a rear end out of a 1996-2001 Explorer which has disc brakes. And a lot of them have 3.55 or 3.73 gears, many with the Traction-Lok limited slip differential. But doing the Explorer swap requires a lot of modification and work to install whereas the 8" swap is a bolt-in swap.
thank you!!
 

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OK, changing from a 6 to a V8. What about the brakes as this is an increase in weight? A v8 rear end will have biger brakes, so, do check on upping the front brakes too eh?
 

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Discussion Starter #9
OK, changing from a 6 to a V8. What about the brakes as this is an increase in weight? A v8 rear end will have biger brakes, so, do check on upping the front brakes too eh?
[/QUOTE/]


yessir plan on going to 5 lugs with disc brakes
 

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68 Mustang Coupe
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The explorer 8.8 can be swapped in with minimal effort. Some have left width as is, welded spring perches on, got the brake line adapter and just compensated the extra width in their wheel selection. The offset diff doesn't seem to be an issue unless the car is lowered considerably.
 

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You may want to consider swapping in the complete V8 steering, suspension and brake system before touching the engine. Have the foundation for the V8 in place first, so the car can handle the added weight and power.
 

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Ideally a 8" from a 65-66 Mustang. The 67-70 8" or 9" will fit however the axle housing is 2" wider . That might make wheel selection problematic. Another great option, the 75-81 Granada 8". Same width for the spring pads and just a touch narrower. They typically had 3.00 gears along with a stronger carrier then the 65-66 8". If there is a down side is that the axle housing doesn't neck down at the spring pad. You will have to redrill for the spring U bolts. It will also cause the back to sit very slightly lower. The Granada may be your best option.
 

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hello!
i am in the works of swapping out a 200ci for a v8.
a problem i’m currently having is what differential to swap in.

my car is currently a 65 with a 2.83 open diff.

what would be a better differential to handle that extra power from a 302
Start a Build Thread, I’d like to follow!
 

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1965 Ford Mustang
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Discussion Starter #15
Ideally a 8" from a 65-66 Mustang. The 67-70 8" or 9" will fit however the axle housing is 2" wider . That might make wheel selection problematic. Another great option, the 75-81 Granada 8". Same width for the spring pads and just a touch narrower. They typically had 3.00 gears along with a stronger carrier then the 65-66 8". If there is a down side is that the axle housing doesn't neck down at the spring pad. You will have to redrill for the spring U bolts. It will also cause the back to sit very slightly lower. The Granada may be your best option.
Im looking on facebook market place, and someone is selling a mid 70s granada diff. He selling two, 3.00 and 2.79 open
 

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There’s another section that’s for documenting Builds.


Give us a run down of the car, a little background on you and how you obtained the car and post pics, documenting the work,.....

I’ll be following!
 

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68 Mustang Coupe
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Im looking on facebook market place, and someone is selling a mid 70s granada diff. He selling two, 3.00 and 2.79 open
Just the diff or the entire housing?
 

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68 Mustang Coupe
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3,286 Posts
If the price is right, jump on them. While the gearing may not be ideal, itll get your car moving.
 
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